Ok that unit is a convertable desktop and has TWO pci slots that can be utillized for installing a pci graphics card. There are some functions that you must do in the bios(set up) so as to be able to use the card after it is installed.
Enter system setup and make sure that Primary Video Controller under the Integrated Devices option is set correctly. Then exit system setup properly to save the information, and reboot the computer.
For a PCI expansion card, set Primary Video Controller to Auto.
to enter set up:
Turn on (or restart) your computer.
When Press <F2> to Enter Setup appears in the upper-right corner of the screen, press <F2> immediately.
If you wait too long and the Microsoft® Windows® Windows logo appears, continue to wait until you see the Windows desktop. Then shut down your computer and try again.
You may be able to return that AGP card to where you got it and exchange it for a PCI video card of like designs.
Now the computer you have is designed for business applications and not really set up for use as high end gaming... Don't expect miracles from it and this is about all you can do to upgrade the computer also.As a business machine the unit is a great workhorse with some great security features for adminastrators.
Hope this all helps you