I'm going to assume your OS is vista/7
Open the start menu.
Search dxdiag.
Click dxdiag.
Post results from general/display tab.
how is that helpful?
maybe im just too tired to figure out, but it seems as he OPENED HIS COMPUTER AND COULD ONLY FIND THE GPU, AND DIDNT KNOW WHAT EVERYTHING ELSE WAS?
anyways, maybe this helps?

expansion card being the card that uses any of your PCI-E slots, like a GPU in case you didnt know that
and the power supply is sometimes located at the bottom instead of the top, usually gaming chassis' though
and on top of the processor is a big metal thing with fans and copper tubing located, which is used to cool the processor. in case you didnt know that