An unforseen problem with Dell computers is that some of the cases and PSUs they make are made as proprietary products, meaning that the girth and overall length of the 7800 GTX might not fit in the case nor will the PSU be able to handle the wattage of the card. You'll have to upgrade your motherboard to PCI-E to run the 7800 GTX and that probably means buying a new proc. memory and so forth. If you can spare the cash, it looks like a better idea for running that card would be to buy a new system since upgrading your exsisting system might not be worth it.