I generally use FireFox, Thunderbird and OpenOffice. I have MS Office 97, which is used infrequently.
After the first series of crashes, I scanned the computer with SuperAntiSpyware, MalwareBytes and AVG 9.0, all free editions. Nothing was found.
After last evening's crash, I updated to FireFox 3.6. I also replaced IE8 with IE7. We'll see what transpires.
Thanks for the suggestions.
Now I wish I had been using TrueImage, etc.
seacue