Yesturday I was compressing stuff on my hard drive to save space, and my computer shut down completly in the middle of it. I restarted and continued and it was fine. Today I was unraring some stuff and it did it again. I restarted, tried unraring again, and it did it again. So I was thinking that mabey I should defragment my drive, and it shut down again. What is going on?