DELL XPS Gen 4 Graphics Problem

I have a DELL XPS Gen 4 desktop PC from 2005, and if I go to boot it up (with the graphics card in), it gives me the following light code:

A (green) B (orange) C (green) D (green)       (1-x-3-4)
(A PCI failure, no PCI cards are even in PC besides graphics)

30 seconds later...

A (orange) B (green) C (orange) D (green)    (x-2-x-4) 
(Indicating a graphics card problem)

If I take out the graphics card, the DELL boots up fine into XP, but its useless to me if the motherboard has no on-board graphics, so please help. If anybody asks, the graphics cards I have tried are nVIDIA GeForce 6800 series 256MB(have 2 of these cards), and a new nVIDIA GeForce 210 512MB.

If I have too, what motherboards (ASUS) that will work with this PC? I am thinking about just buying a motherboard (not DELL's) and put it in there. Honestly, I hate DELL computers. But it is a bummer when you only have a laptop to work with:

Gateway NV5378u

4GB DDR2 RAM
2.1GHz AMD Athlon II X2 M320,
256MB ATI Radeon HD 4200
500GB HDD
15.6in Widescreen Display
Windows 7 Pro x64 

Thanks!