no video, video card not working

i was playing Knight Online with my nVidia geforce mx mx 400, when suddenly i started noticing some bad graphics, so i exited the game. when it showed my desktop, it was at 800x600 ( i usually have it a 1152x864) and when i tried to change the resolution back to where it used to be, i got a messege saying that the card was made for an older version of windows. thing is, i havent done any updates lately, and i had run the game perfectly after the service pack2 came out. now i cant see anything when i plug my monitor to that video card.
thnx in advance


ps. i tried the video card on another pc running on windows xp but without the latest updates and the card works perfectly fine.

Update the drivers, and then see how it works.