Sounds like one of those painful 'disable device X for a little while' type deals to me. I haven't had any stability issues with 7 - what's your windows update setting? Have you installed updates lately?

I used to monitor them pretty closely on XP but am happily installing all 'important updates' on 7 with good results so far.

And what virus scanner are you using? Those things can get a little overzealous; maybe yours is attacking valid processes?