In addition to Griff's answer, I would recommend you to issue these commands in a console:
/* Schedules a full system partition check on last reboot */
chkdsk c: /r
/* Answer 'yes' to the question */
/* Reboots */
shutdown /r /f /t 0
/* This may take a while, depending on your hardware and the size of the partition */
I have often seen this test reveal a hard-drive failure when the temperature of the drive goes up.
Moreover, it will check that your drive is not in a bad state due to the initial hard reset.