system shutdown after installing AMD Opteron 180

Hi, I just installed a AMD Opteron 180 dual 2.4 up from a AMD Athlon64 Processor 3800 single 2.4 and on the initial boot into Windows XP it installed the new hardware and needed a restart. Upon the next restart it got to the Windows loading screen then completely powered down and every subsequent time after that it does the same thing..its just compeltely shuts down. I went into the BIOS and it even shut down just sitting in bios. I am guessing this is a power supply problem, yes? My power supply is a 350w. I've seen similar posts on other sites about this CPU having problems but they were saying they were just getting automatic restarts and the solution was to just reinstall windows. Any help would be great, thank you!

What mobo is it?

Might need a flash to the bios to recognise the dual core.

Or windows might have had a fit because the dual core little utility from AMD isn't there ... dunno if that would cause it to lockup and reboot tho.

Alternatively the cpu might need to be reseated properly - it could be overheating ... boot to bios and check the temps there first ... then if too hot just shutdown and remove cpu, clean, reapply thermal paste, reseat, lock down HSF and try again.