Roze
Hiding behind a mystery
Yes, mine and my wife's both restart randomly, usually when starting an app. Common example is zynga poker, happens often with that one, but other apps too occasionally. Wife has issue with browser becoming non-responsive, and pictures taken disappearing from the gallery also.
Have you done a factory reset on you Atrix? If you did, did that help?

I haven't had such issue with my Atrix since I've gotten it.
You're not rooted are you?