hey, dude u were right i checked that whether there is a video card installed or not. and yes it was not installed. but i don't know that which one is my card. actually i also run the direct x window in which there was problem,i.e. that my computer is using another graphics card and there is no 3D acceleration active.
GPU-Z would have detected an integrated card. If you have a card installed and you are running it without the drivers it will not recognize it since it is running of the win basic VGA driver.
Where do you have your monitor cable hooked up?
If you go into device manager under graphics adapters is there any thing with problems?