I recently had many experiences of my email program (microsoft outlook) just hanging. If I did some surfing and then came back to it, it would perhaps work. I had the same problem when looking at web pages,(no activity on the litte blue screens).
However since updating to SP2 from the pc advisor cover disc, everything works fine. Could it have been a microsoft update causing the problem?
If you haven't updated to SP2 its certainly worth a try