enable AGP as the first video search. it shouldn't help anything. it just tells the system during the boot to search for an AGP "card" rather than waste time [milliseconds] looking for a PCI card. once the AGP card is "found" you are running from the AGP slot.
ATI drivers can give one fits. I can't help you there.
I haven't done this in a while, and can't find the info on how to change the graphics settings from pci to agp. I'm having some trouble with my tv tuner card It is ATI) and this is something that might help. Can you tell me in simple terms, cause I did it before, but it has been awhile. I'm using ME