Before i upgraded from windows xp to windows 7, world of warcraft worked perfectly fine. After i started to play it on windows 7, it says "World of Warcraft was unable to start up 3d Acceleration". I have no video card in my machine, and don't tell me to buy one because it worked before without one. How can i make World of Warcraft playable again?

I have uninstalled it and reinstalled it, but nothing. I tried repairing, but nothing. I have updated my video drivers and installed directx 9.0c, and still nothing is working.