You pay attention to see when you turn on the computer, whether you see the computer self-test? If you can not see, you have to consider whether the graphics card or monitor failure, because you this kind of failure, very much like the graphics card failure caused by, to put it bluntly, is that the computer is running normally, but the graphics card can not be displayed, of course, you can not see anything. If you can see the computer self-test, then the problem in the operating system is more likely, you can use the CD repair to install the system to solve.
And your computer does not have a CD-ROM drive, in which case I think it's just a matter of finding the repair department!