I have read alot of similiar problems that I have had after installing SP2. My system basically crashed. It kept restarting and then a few times later I got the "wonderful" BLUE SCREEN.
I have a water cooled:
AMD64 3200+ oc'ed
Shuttle AN50R mobo
ATI 9800 pro video oc'ed,
1GB of Mushkin ddr 3200,
raid 0 36GB RAPTOR(10,000rpm)
and Maxtor 120GB(7200rpm) IDE-133 slave harddrive
SONY DVD+-RW
Artec CD-RW

I have tried installing it twice, and both times had to reinstall Windows on my machine.
In my opinion if SP2 is not willing to cooperate with this hardware then it is NOT ready. But then again it's not the first time that Microsoft F#$%'ED up again. We'll wait and see.