12 hours is way beyond what would be reasonable.
Right click on "My Computer" and select "manage" from the context menu.
Expand the little plus labeled "Event Viewer".
Click on the item "System".
If you see a lot of red stop signs that mention disk devices then you probably have a serious problem with your disk drive that would not be something you would likely fix yourself.
Okay, I did that and it didn't give me any stop signs or anything, but it does say
system error records 512
application error records 512
security audit records 512