Why wont Star Wars Knights of the old republic 2 the sith lords work on my computer?

[Jackson]

it used to work then it got uninstalled and when i reinstalled it, it told me my graphic card didnt meet the minimum requirement. after that when i try to play it goes black and then goes back to the desktop with except everything is enlarged and the game is in the tool bar at the bottom and isnt responding. i am confused as to why it worked before and not now. i know its not because of the cd because i can play it on a friends computer fine, but his is newer. I am just asking what i can do without going to bestbuy and buying a new graphic card for 100 dollars. I have Windows XP