This has happened to me before. The problem is that sometimes when I am doing random stuff on my PC, it makes aclicking noise and stops working, a complete freeze. The clicking noise goes on with a 2 second period between each click. In the past, I used to take out all my components out, cleaned them up and put them back and they usually worked again. I think the problem is with the Hard drive as I think it's the source of the clicking noise. Any ideas?