NO VGA OUTPUT(when I install a new video card)!!!!?

I have a core 2 duo 3g ram, its in msi motherboard and currently it runs with its built in video CARD.. now i got this video card (from my old hp computer) a palit 9500gt, it runs normally there... now i tried installing it in my new pc which d 1st one i mention, but when i start the pc its sayz "No Vga Output"??? im sure the card is ok since it runs normally in my hp... i tried checking of there is any loose contact or anything but i really dont know... pls help.. ^_^|||Hope this helps.