The processor is older and pretty slow ... your video card is very low end ... the motherboard is old ... your RAM isn't a great amount but that shouldn't have a great affect on gaming ... your HDD is also pretty old, and slow, which again wouldn't affect game performance but would affect load times, as well as the responsiveness of the machine. Where did you get this from? I hope you didn't pay much for it. I'm sorry to be the bearer of bad news but it may not be worth putting money into that system ...
P.S. Welcome to the forums.