Freezing Up

[Tim]

While using a pull-down menu or pop-up menu, my screen
will lock up and I can't even do Ctrl-Alt-Del to bring it
back to life. I must do a hard reboot and do disk check.
Some days it will be fine. Other days (like today) it
will freeze up three to four times a day. This only
started about three weeks ago. I have recently installed
Norton's to see if it was being caused by a virus.
Norton's says no virus found. I have reinstalled IE5
(because it was mainly happening while I was online, but
not always), and this did not help either. Can someone
please tell me what my problem might be? Please email me.
Remove NOSPAM from my email addy. Thanks in advance.

Tim