ram 'n' video card help

so im upgrading a new compaq i was given and just putting in a video card and 1 or 2 gigs of RAM, it already has 1gig. im thinking about the 7900gs and not sure on ram yet. now for the ?'s....is the video card good for WoW and other gaming of that type.is the video card reliable.is it possible for a video card to not be compatible with a PCand lastly, should i get 1 gig or 2 gigs and what should i gethelp much appriciatedram 'n' video card help
Can you tell us anything else about the PC? What model is it? What processor, motherboard, and anything you know about the power supply. If it is a new system, it probably takes DDR2 RAM. Depending on the RAM in it now, you can add a gig or two of similar RAM. The motherboard/BIOS will determine how many sticks, what size and speed of RAM is supported. Depending on the power supply, you might (probably will) need to upgrade it to add a decent gaming video card.ram 'n' video card help
If you have a decent power supply, then that card will max out W.O.W. Go here and see if you have a pci-express slot or AGP. http://www.gamespot.com/features/6142716/index.html Ifyou have an AGP slot, then that card will not work as it will not fit in your slot.