Here are several great hard drive stress testers to push your hard drive to the limit before the drive give up and has to be replaced. If your having drive problems. Your best bet is to test the hard drive via stress testing and verify that it's still good to be used.
Segate
Hitachi
Windows
Samsung
Western Digital
BartPE
Fijitsu
Segate
Hitachi
Windows
Samsung
Western Digital
BartPE
Fijitsu