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.
The simplest potential fix is to open the Device Manager, right-click and Uninstall, followed by a reboot. And since their website is down or whatever I cannot determine the NIC Mfg. If the NIC is produced by e.g. http://www.realtek.com.tw/ then simply D/L and install their latest drivers for the either 64/32-bit version corresponding to your OS.