Flash, you can disable the "on-board" video by going into the BIOs when your computer boots up.
First check to see if you have an AGP slot on your mother board...smaller brown plug. If you do have one that pick your self up a new video card, spend at least $100.
set your display properties to standard VGA, and shut down your computer.
install the new video card and boot computer.
when BIOs splash screen comes on enter BIOs...most times its hitting the "delete" key.
using the keys to move around find your old video and disable it. Save the chanfes and exit.
when your computer reboots it should spot the new video card and start the set-up wizard.
...or you could drop it off at a good computer shop and pay them to pop a new card in it.