If I shut down windows or hold the power button to force the system off, it restarts about one second after it shuts off. The only way to shut if off is to catch it between POST and boot with a single click of the power button?
Has anyone ever heard of this? Any fixes? Is the the PSU or motherboard?
I've built 20 systems on this motherboard, and some users complain that sometimes they find their computer switched on the next morning. Obviously after they shutdown their computer restarts.
From a brief investigation I did, it appears they restart randomly - even after hours that they shutdown.
I am guessing we have a similar problem. I would exclude the power supply as my systems have various power supplies.
My setup is similar:
Win XP Sp3
Athlon 64 X2 5000+ Black
Gigabyte GA-MA78GM-S2H (Bios Version F3)
Kingston 2x1GB 1066MHz
Various power supplies
You did not mention your OS, but comparing our setups, it appears that excluding the motherboard we have at least 1 more thing common - the memory type. However since you are on phenom, your memory runs at 1066MHz while mine is running at 800Mhz.