I had a similar problem with a Dell desktop - yanked Vista and installed XP Pro - been happy ever since...a lot of my software wouldn’t work with vista and it is notoriously unstable...
Wish I could use a desktop but, alas, the new comp travels with me as my old one did... I bought two of them at the same time, one was for my brother, and he had the exact same problem...not sure what causes it, but Dell customer support line doesnt seem to do any good with it
I love XP Pro too. FWIW, I’ve been running Windows 7 beta for about a month now. I like it so much that I have replaced all my Vista and XP installations with it. Everything works like a charm. Even on a 6yr old 1GB P4 box. MS may have gotten something right for once.