I have been having persistent trouble with an nvidia graphics card - i keep getting a nv4_disp error. i reinstalled the video driver and this seemed to cure the problem. then i installed jaws screen reader and it gave a message that the software basically wasn't compatible with nvidia so i aborted the installation of jaws. then the next day i got the nv4_disp error again. i use win xp pro and the computer (a dell laptop) is only a few weeks old. should i replace the graphics card??