Re: Dell xps 400 Graphics Card
Turn off your computer and open up the case, since this is a BTX motherboard look up where the pci slots on the top and see if you see a videocard with a heatsink on it.
Some video cards are green, blue, or red and will have a heatsink or fan attached to it.
Release the lever on the pci-e slot which is a black slot turn over the card and look for a model number on the back of it, it should be a white label.
Give that to us and we should be able to track down that video card fairly quickly.