The solution that the computer can't be turned on after normal shutdown 1 1. Check whether the monitor and the host cable and connector are connected normally;
2. If the system has started normally, you can check whether the button to turn off the power switch is normal when the display screen above the keyboard is turned off;
3. If there is no problem with the power-off switch of the monitor and the pop-up display screen, but the monitor cannot display, it may be a system problem;
4. Check whether the display is black when dos is started. If a black screen is displayed when DOS is turned on, and there is no normal self-check sound, it is mostly a system failure;
5. Number five. The BIOS startup disk settings may be incorrect. Solution: press F2/f10/f12/delete (depending on the motherboard) to enter the BIOS, and change the USB of the first boot item 1st to Hard Deice, and press F 10-Y in turn to save the settings;
6. Hard disk MBR can reset errors with DiskGenius;
7. Take out external devices such as CD-ROM drive, USB flash drive and floppy disk and try to start it;
8. Press F8 to enter the mode, and select the last correct configuration or normal startup;
9. Disassemble the chassis of the desktop computer, unplug the hard disk cable and reconnect it to see if it can be started; Pay attention to whether the hard disk rotates normally during the boot process and touch it with your hands;
10. General method: reinstall the system.
Solution to the problem that the computer can't be turned on after normal shutdown 2 1. If there is a problem with the power supply or the bios setting of the motherboard, remove the motherboard battery for a long time before putting it back to try. If the user doesn't know where the motherboard battery is for reference, the startup test fault still exists.
2. If you suspect that there is something wrong with the power supply, unplug the original power supply and plug it in again, and start the test to see if the fault has been solved. If it hasn't been solved, you can only change a new power supply or a good old power supply, and this fault can be solved. It is through the second method that I solved the problem that the computer can't start and the CPU fan stops.
Solution 3 (1): First, check whether the external power supply is normal and unstable.
If someone else's computer is normal on the same power supply, there is basically no problem with the external power supply. Then check whether some sockets have problems (such as poor contact of sockets, etc.). )? Did the fuse in the socket blow? It is best to measure the voltage with a multimeter.
(2) See if KB and mouse interface are connected backwards. If the computer has this problem, the keyboard and mouse will not work, and some computers will not even start.
(3) Troubleshooting: Unplug irrelevant external devices, such as devices on the sound card interface (such as speakers), LPT ports (such as printers), two COM ports (such as external modems), KB and mouse, network cable and USB devices. After unplugging each peripheral (note: turn off the power before unplugging), turn on the power and try to determine which component is faulty.
(4) Unplug the ATX power cord plugged into the motherboard power interface (there are two rows of ATX power connectors with ***20 connectors. If it is a P4 motherboard, you have to dial out the +/- 12V power cord; For the old P4 motherboard, you must dial out the auxiliary power cord). Then plug it in and try again. If not, proceed to the next step.
(5) When starting the machine, carefully check whether the power box fan or CPU fan rotates. If it stops after a turn, generally speaking, it may be a short circuit of computer components (such as power supply itself, external equipment, board card inside the host, etc.). ), or the power provided by the power box may be insufficient. At this point, you can press Next.
(6) Disconnect the power cord of all devices (such as optical drive, floppy drive, hard disk, etc.) powered by ATX power box. ). Then unplug the ATX power cord plugged into the motherboard power connector. Because the combination of green (ATX-only) and black uses the switch connector equivalent to ATX power supply, they are connected by wires. If the power fan rotates, it means that there are probably short-circuited components in the newly unplugged equipment (because the power box was basically idling just now, that is, there is no load, so it is also possible that the power provided by the power box itself is not enough. If possible, try replacing the power box. If the power box works normally, skip this step).
Plug the power connector provided by the power box back into the motherboard. If the computer still won't start, please take the following steps.
Description: As we know, as the switching power supply of the computer, it is the "power supply" of the computer.
(7) Check whether the power switch interface (power switch/on/off) of the motherboard is normal.
Unplug the power cord on the motherboard, and short-circuit the two power switch pins on the motherboard with a wire or screwdriver to see if the computer can start. If it can be started, it means that there is something wrong with the switch part of the power supply (such as an open circuit in the internal circuit wrapped by the heat shrinkable tube). ) and it can be eliminated.
(8) Check whether the switch and indicator light on the motherboard and the chassis panel are connected normally, such as whether the reset key is short-circuited. Follow the signs in the motherboard or motherboard manual. If there is a problem, connect it according to the correct marking method. Note: If the wiring between the motherboard and the chassis panel is unplugged, the original correct wiring record should be made for the next recovery.
Solution to the problem that the computer can't be turned on after normal shutdown 4 There is a high probability that there is something wrong with the battery. You can try to remove the battery and use the power cord to supply power directly. If it can be turned on and off normally, it is a battery problem. If the fault still exists, you can try to solve it according to the following detection and repair methods from soft to hard:
Turn it off first, then turn on the main chassis, unplug the power cable and data cable of the hard disk, plug it in after 2 minutes, and try again. Then repair the system as follows:
Press F8 key continuously to enter the system operation menu when booting (in the case of Win8, Win8. 1 and Win 10 systems, press and hold the power button to turn it off after seeing the boot screen, and you can enter WinRE {Windows Recovery Environment} after repeating it for about three times in a short time, but some users may need to directly disconnect the power. In this way, the advanced recovery interface should appear after booting. In the advanced reply interface, select Enter Safe Mode.
First, by soft: trying to repair the operating system:
1. If there are external devices, such as USB flash drive and USB mobile hard disk, or there is a memory card in the card reader, please take it out and try again.
2. Remove and install non-standard components, such as memory and hard disk. It is recommended that you contact the operator to remove the added component and try again.
3. Enter the computer BIOS check? Whether the hard disk can still be recognized in the BIOS, and select the option of "Load Best Default Value" or "Optimize Default Value" to restore the BIOS default settings, and then test.
4. Press F8 key continuously to enter the system operation menu (in the case of Win8, Win8. 1 and Win 10 systems, after seeing the boot screen, press and hold the power button to turn it off, and repeat it for about three times in a short time to enter WinRE {Windows Recovery Environment), but some users may need to disconnect the power directly. So the advanced recovery interface should appear after booting), select "Last Correct Configuration" and restart the computer to see if it can be solved.
5. Press F8 key continuously to enter the system operation menu (in the case of Win8, Win8. 1, Win 10 systems, after seeing the boot screen, press and hold the power button to turn it off, and repeat it for about three times in a short time to enter WinRE {Windows Recovery Environment}, but some users may need to directly disconnect the power. Advanced recovery interface should appear after booting), then look for "safe mode" and enter "safe mode". If you can successfully enter, click Start → All Programs → Accessories → System Tools → System Restore to open the System Restore dialog box and select "Restore my computer to an earlier time". In this way, you can use the system restore function of Windows system to restore to the restore point where you can boot normally before. (If any)
6. Install the CD or USB flash drive with the system, insert the CD-ROM drive or USB interface, restart the computer, and enter the CD-ROM installation system state or USB flash drive installation system state. After the startup interface flashes, do not choose to install the system, but choose to repair the current system (it may run for a long time, 2-4 hours), and wait patiently for the repair to be completed to see if the problem can be solved. (At the end of this paper, the method of setting U disk as the first boot sequence device is described in detail. )
7. Unstable hardware devices, outdated device drivers and interference from third-party programs can also lead to black or blue screens. It is recommended to enter the safe mode first, and evaluate whether the reason is the expired driver or the interference of the third-party program. At this time, please download the latest BIOS, sound card or graphics card from the computer manufacturer's website and update it to solve the problem.
If the above seven methods are ineffective, you can only reinstall the system.
Second, come hard: see if it is a hardware problem:
1, the battery of the motherboard button is dead, so the saving time will be lost after power failure, and the information will not be saved. Try a new battery.
2, the motherboard BIOS error, some motherboards have anti-intrusion mechanism. If the accessories have been replaced recently, it may also be caused by an error in the motherboard BIOS. The solution is to press the DEL key (or the key prompted by the boot screen) to enter the motherboard BIOS and initialize the BIOS setting information. Usually press F9 to restore the factory default settings, and then press F 10 to save, exit and restart the computer.
3. CMOS(BIOS) settings are wrong, mainly because there is something wrong with the options of software settings. After booting, you can enter the Bios for setting.
At this point, you can check whether your machine has a floppy drive, CD-ROM drive or other accessories [such as a graphics card]. If you don't have these hardware, but your computer has these settings, you can try to turn off these options or set them to be disabled.
[Note: CD/DVD/CD-RW drive: CD-RW device: floppy disk drive: floppy disk device: floppy disk device]
4. The original part of 4.cmos(BIOS) conflicts with the current hardware. Before the CMOS(BIOS) can discharge, there is a CMOS three-pin jumper next to the button cell of the motherboard, but generally two pins are connected together. At this time, you can pull out the jump cap, connect the two pins together, and discharge with the jump cap in the case of power failure [this process usually takes about 4 seconds]. And then restore it to its original state. Or unplug the button cell, put it upside down, wait for 5-6 seconds to discharge, and then restore it to its original state. After booting, you can enter CMOS(BIOS) to restore the default settings.
5. Whether the graphics card driver is not installed or damaged, and the solution; Update the graphics card driver, use the driver CD that comes with the computer or go to the graphics card official website to download the latest driver, update the graphics card driver, or go to the Driver Home website to download the latest version of the driver wizard and upgrade the graphics card driver;
6. If the hard disk can't be detected, you can try to change the data cable for the hard disk. If there is no cable, you can also try to switch the two ends of the data cable and change the interface on the motherboard.
7. If the hard disk is still invalid after changing the data cable, you can also try to unplug the data cable of the hard disk before starting the test. See if it will still be stuck on the LOGO screen. If you can pass the LOGO interface, it is estimated that the hard disk is out of order. Enter the BIOS to find the hard disk or enter the PE system to check the health of the hard disk. If the hard disk is unreadable or proved damaged, it must be replaced.
8. Poor hardware contact is mainly manifested in poor contact between the graphics card or memory chip and the motherboard. At this time, you can unplug the graphics card or memory module. Unplugging the graphics card or memory module will not affect the access to cmos interface when booting. At this time, if there is no error in CMOS(BIOS) setting when entering this interface, it can be concluded that it is a problem with the graphics card or memory stick. You can use a better eraser to check the contact part with the motherboard first, and the memory is also eraser.
9. There are conflicts between different storage blocks of hard disk and CD-ROM drive. You can check them one by one at this time. You can unplug the power cable and data cable of the CD-ROM drive first, and then try to check with only one memory.
10, check whether there are external devices connected to the machine. External devices such as USB flash drive and mobile hard disk may be plugged into the USB port of the computer and forgotten to unplug it, resulting in the failure of the motherboard self-test card. The solution is to unplug the extra external devices and restart the computer.
1 1, check whether the keyboard and mouse are connected backwards. This refers to the keyboard and mouse with PS/2 interface. Many people are careless and plug the interface of the keyboard and mouse backwards, which leads to the self-check error of the boot computer and even the screen is stuck. The solution is to turn off the computer first and then take over the keyboard and mouse again. Usually the purple interface is the keyboard and the green interface is the mouse.
12, maybe there is something wrong with the motherboard itself. You can check whether the battery circuit of the motherboard is broken or whether a capacitor is blown. If so, weld and replace it yourself or ask a computer maintenance person to weld and replace a capacitor with the same specification for you. If the motherboard is broken, you have to buy a new one and install it.
13, the chassis is not clean. The CPU fan is too dusty to work normally, resulting in the CPU temperature being too high. Clean the dust on the inner wall of the chassis, CPU fan, graphics card fan and motherboard with a brush and a hair dryer.
The solution that the computer can't be turned on after normal shutdown 5. The computer cannot be turned on for the following reasons:
1, the host is not powered on. First, check whether the indicator light on the chassis is on, and put your hand on the power fan to see if the power fan is rotating, so as to judge whether the host is powered on. If the host is turned on normally, then see if the indicator light on the display is on. If the indicator light indicates that the monitor is normally powered on, and both of them are normally powered on, then the power failure is basically eliminated. You can see the next step. If the computer host or monitor is not turned on normally, the power failure is not caused by the above problems. At this time, you can ask professional maintenance personnel to repair it.
2. The computer still can't be turned on when the above host and monitor are powered on normally. At this time, you can see whether the socket of the monitor and the graphics card is in good contact, and you can unplug the plug to check whether the D-socket is bent, broken and a lot of dirt, which is a problem that many users often encounter. When connecting the D-socket, the pin in the D-socket is broken or bent due to uneven stress, forgetting to tighten the socket fixing screw, or improper installation method and excessive force, resulting in poor contact.
3. If the reason of poor contact between the graphics card and the monitor is ruled out, you can disassemble the host at this time, and check whether the graphics card of the host is in good contact with the graphics card slot, whether the graphics card is normal, and whether the graphics card or slot is dusty due to too long use, resulting in poor contact? Are there any signs of burning and cracking on the chip on the graphics card? When the graphics card causes a black screen, there will be a short and long "beep" sound prompt when the computer starts self-checking. Try another good graphics card.
4. If you still can't boot after troubleshooting the graphics card, it is also possible that the computer can't boot due to poor contact between the memory card, CPU and hard disk socket. These plates are not in good contact. Usually, after the computer is turned on, the computer alarm cannot enter the system. Any siren sounds. The "whistle" when the computer starts is caused by hardware error or damage. This failure depends on different alarm sounds. You can remove the corresponding board, clean the dust and rust at the contact, and then plug it in to repair the hardware.
The following is to judge which hardware is out of order from the computer alarm sound:
1long1short: Error in RAM or motherboard. Try to change your memory. If it still doesn't work, we will change the motherboard.
1 long 2 short: monitor or graphics card error.
1 Length 3 is short: keyboard controller error. Check the motherboard.
1 length 9 short: the Flash RAM or EPROM of the motherboard is wrong, and the BIOS is damaged. Try changing the flash memory.
Constant ringing (long sound): The memory module is not tightly inserted or damaged. Reinsert the memory stick. If it still doesn't work, you need to change a memory.
Repeat short ring: there is something wrong with the power supply.
5. When the machine can't be turned on after hardware troubleshooting, it is basically caused by system failure. At this time, press F8 when turning on the machine until the advanced option appears. Select "Last Good Configuration" and enter the repair. Press F8 to enter safe mode when turning on the machine, and then exit. When starting up, choose to restart or shut down, and then you can enter the normal mode (repair the registry).
6. If the fault still exists, there is a serious problem in the system. At this time, you can consider reinstalling the system. If your computer has previously installed a system backup and backed up the system, you can restore the system with just one click.
The solution that the computer can't be turned on after normal shutdown. If you click the power button, the computer will not respond, and even the display screen will not light up. If the notebook recommends maintenance.
If it is a desktop with strong hands-on ability, you can open the chassis to see if the hard disk cable is firmly connected, or unplug the memory stick, first wipe the gold finger of the memory stick with a clean towel or paper towel, then put it back in its original position and restart it to see the effect. If it still doesn't work, it is recommended to send it for repair.
The display will light up.
First of all, when you turn on the computer, try to keep pressing the F8 key on the keyboard (not pressing it). If the safe mode menu cannot pop up, it is also recommended to send it for repair.
If the safe mode menu can pop up, it is recommended to try to use the last correct configuration mode first.
If it doesn't work, try safe mode again.
If the security mode has no solution; If possible, it can be repaired with PE.