Fitting Graphics Card Into My PC

My computer is a a6554f HP and it has one PCI-E slot. However when i tryed to fit my friends old video card from the back in, the slot was too short. The fan on top would hit and even if i took that off, the plug area itself was about 3/4 of an inch tall. I measured the slot height on the computer and it was only 1/2 an inch tall... Right above the slot is a divider between the PCI-E slot and another slot. Are the newer video cards like the EVGA 9800 GT thinner than older ones? Does anyone know what I can do to make them fit? Why the hell would HP make a slot so damn thin?

Anyways.. please respond.

its a normal size case, just the expansion slots on the back are so thin, only 1/2 an inch tall. Only thing i can think of is knock out the metal bar seperating the 2 slots and use 2 slots.

Its the only slot available since the top slot is taken by somthing already. The only expasion slot is the PCI-E Slot . The card would fit into the slot its just i cant fit the card thru the back of the computer since it is only 1/2 an inch tall opening. The videocard i tryed to fit in was 3/4 inch.

Like i said between the 2 back openings there is a thin metal bar, maybe I could hit that out? lol. then there would be a little space above the videocard but meh at least itd fit