Re: Very Strange Issue - 4GB ram
That is an odd one. Try unistalling the drivers and physically removing the card. Reboot, then reinstall the card and it's drivers. maybe the system is having difficulty allocating physical address space for the PCI card.
On the other hand, I think you would be better off using the built in nForce Gigabit LAN. In my experience with that motherboard, it ran faster then the Intel counterpart in another system I had.