I tend to purchase my PCs one to two years out of date, so I can sympathize with you and your outdated machine. Budget never seems to allow for a Super-PC...
It would seem to be enough hardware-wise but when he installed the game it was un-palyable.
What do you mean by un-playable? Frame-drops? Unresponsive? Audio glitches? Online lag?
One of my sons is wanting to play Age of Empires 3 on the game cab but the machine inside is a little outdated for it. (works great for mame). Heres' the specs:
# 2.5gig CPU
# 512mb ram
# on-board graphics (don't know the specs for it)
Seems like the CPU should be OK, but the RAM ought to be bumped to at least 1Gb.
If your son wants to play any graphics-intense PC-based games, then you'll need to get off of the onboard GPU. The trouble is the sub-$200 market for GPUs is not all that great. Check out an
ATI X1950; I've heard generally good things about this card, and, for under $150, it's the right price. I think most are PCIx, so you'll need to check your system support. Also, make sure your PC case can accomodate a full-size PCI card; most of these GPUs are
loong.
I don't game, but know when editing video, XP processes can be killers. Make sure
nothing is running in the background and take some of the XP bling down (try Windows Classic Theme). Optimize the OS as much as you can...