I would test the hard drive to check if it has failed.
If you have installed the drive in your rig as a second drive so you can still run your Windows on your rig, test your friend's hard drive with "Seagate SeaTools for Windows" which can test any brand of drive. Click "Downloads" on this page: http://www.seagate.com/support/downloads/seatools/
Select your Windows version, then click the "Download" button.
Install it, then open it.
Select your friend's hard drive and run both the "Short" & "Long/Extended" tests on it.
If you see "Failed" after testing it, your friend needs a new hard drive.