Upgrade upgrade upgrade.
I was never too thrilled with “upgrades,” I’m more of a revision type of person. Your son wants to play Empire Earth right? Then you need three important things: RAM, CPU, Graphics Card. And of course the motherboard (with the chipset) that supports all that. Also, your 2x13GB HDDs might need to be a lil bigger but it doesnt seem like an immediate problem.
Lets say you choose Athlon XP, of course the palmino core, its cheaper than P4s that has the same price. Now for motherboard, I’ll recommend a mobo armed with a KT333, you get to use the fastest DDR Ram, PC2700, (as the new KT400’s DDR400 isnt much faster since those RAM are slower, and faster ones are rare), and you get such things as built-in, sound cards, LAN, USB 2, and RAID controllers. I think the best is suppose to be this one by Giga-byte, check out the roundups for KT333 mobos by www.tomshardware.com if you can’t find it, tell me and I’ll do it.
Now for RAM you’ll need 512MB, either buy a stick or 2x256MB, remember RAM is a pc’s best friend…sorta. Last for the graphics card, I don’t know how much you wanna spend. Possible choices are a Geforce4 MX (either 420, 440, or 460 model, I think 440 is most popular, and popular means cheaper) or a Radeon 8500.
If you live in the U.S. go to www.pricewatch.com and dey’ll link u to the store with the best price.
Hope this helps