open the case and see if there is a brown slot, thats agp. there is only one brown slot. and that computer is terrible. celeron is bad for gaming. get a prescot or a northwood type pentium 4 and get a agp 6600gt agp video card. you could get prescot 3.0ghz cheap. if there is no agp slot on the motherboard and you really really want to play games, then change the motherboad with agp or pci express support.