I think Archaic59 covered about everything spec wise. As someone who has had the unfortunate experience of upgrading prebuilts be prepared for a couple of things. Power supplies are often weird and don't always adhere to full ATX standard. While you can usually get them to work you may have to do some cutting on the case for ATX upgrades. Your 250 card needs a minimum of 450 watts. Also if the unit is running on integrated graphics make sure to disable them in bios. System resources are pretty limited on those older units and conflicts can come up. Good luck.