3TB to 64-bit WIN7 system is good. (Don't tell me you're a laptop)
Boot directly from the chassis jumper and see, get into the system and see if disk management is there?
Or download a professional disk utility, such as PQ software and other preliminary detection! In the PE under the detection of the best (in fact, take a CD-ROM system or USB flash drive system, boot into the bios first look at the wood? Or enter the PE system with HDDlife disk utility can also be detected! Sometimes it happens to use these software can also be repaired)
When I first bought it, at least 900 yang, try to take the after-sales to get it. Try to fix it!
Oh buy lumps! After all, 3T ah!
Poor child!