I've done the Google thing on many variants of FireFox lockup, and there are a LOT of them.
My current working opinion: There's something inherent to FireFox 2.00x that causes issues with either or both video and sound card drivers.
What I lack is, how the heck to unbug such a thing?
So, I've switched back to IE, and so far, so good. Well, so far, no crashes / lockups.
Thanks again for your willingness to help. If I have any success, I'll certainly let you know.
rr