right some mainboards along with a "slot" to plug in a vid card, had also a vid card embeded into the mainboard, with the vga connector in with the usb, printer , kb and mouse..so I take it yours only has the plug in AGP or what ever...
Do you still have your manual for the mainboard ?
if not go to you manufacture of your mainboards web site to their support and DL a new one...all mainboards are different.
the instructions are there to clear cmos