BFG nforce 680i, network adapters disable on restart

Hello,

I have a BFG nforce 680i motherboard with windows 7. I was running xp, but since upgrading to 7 everytime the computer restarts the network adapters automatically disable themselves. If i cut the power and let the capacitors discharge. then reboot it works, but only if the power is cut to the system.

Cutting the power works everytime, but shutting down without pulling the power disables the network adapters.

any ideas???

thanks guys