Firstly, try running a chkdsk on the drive.
Open a command prompt as administrator, and type in the following:
chkdsk c: /f /r
It will say it cannot lock drive and ask to run on next restart. Type Y and press Enter. Then reboot the computer and let it run the disk check. It may take a while, especially on steps 4 and 5.
After that, check your RAM. Burn Memtest86+ to a disc, and let it run for a minimum
of 4 hours. Get it from here: Memtest86+ - Advanced Memory Diagnostic Tool
Burn the ISO to a disc using something like ImgBurn (or built-in ISO burner if using WIndows 7).
And again, make sure GPU drivers are updated.