My computer has been acting very strangely recently. When restarted , everything appears fine until after about a day of use, when it becomes VERY slow. I pinpointed the problem to the hard disk when I noticed that the hard disk light stayed on continually when it froze. This happens every day, regardless of what I do. I have defragmented, gotten rid of thirty or so unnecessary startup programs but nothing works. Sometimes, after being slow, it spontaneously becOmes fast. I have to be able to use this every day without constantly restarting. Please tell me if you have any tips on how to fix this problem.