Yes, you have it.
Do the following steps :
1) open the side panel of your chassis and plug out your card.
2) then plug the monitor's VGA/DVI cord into the onboard graphics.http://img836.imageshack.us/img836/2159/resizee.jpg
3) then boot windows and clean all drivers.
4) plug your graphics card back and boot again.
5) install the stable driver back again.
Where can I find the onboard graphics card on a ASUSTek M3N78 Pro motherboard?
Do I have to keep the top off and the plug is inside the computer? or outside? (I removed my main Graphics Card)
Where it shows the inboard graphics card on your pic I don't have anything like that there.
Or, when I removed my PCIe card (which I have to use an adapter to have the white plug convert into the blue plug into the monitor). Next to the PCIe slot the other slot has a plug go directly from the one blue slot and plug directly into the motherboard, is that it? So does that mean it is already plugged in and I just had to remove my graphics card and then start it up?)