SBS 4.5 Video Card

I have a customer with a “custom” built (not by me) NT SBS 4.5 server. At one point in time the server “crashed” and had to be reloaded. Ever since the server was reload, every time the server is rebooted, it says the video drivers failed to load and that NT is using the defauld VGA drivers. I have tried reinstalling the video driver, setting the video to standard VGA, then reloading the correct drivers, and even tried a new video card, nothing works. The server is runnings SP4 and it was reapplied.