I'm looking to build or find a machine that can handle today's games for around $500. I've been using work laptops for the last 10 years or so and would like to get something with a little more power. The last desktop I had I built myself in 1999 or so, it was a pentium III 500 and at the time people were jealous.
Any advice?

Even assuming you can pirate parts from your old computer, your budget is probably not high enough to allow you to build a really good, "killer" gaming computer, since you will want a high quality graphic card, a high speed processor, and several megs of RAM.
John

Can't be done. At $500 your best bet is to get a low-end Dell or similar.

500.00 can get you an entry level E Machine or Acer from places like Circuit City or Best Buy, then you have to spend another 500 to 600 dollars to make it into a decent gaming rig.

I have a word for you...well a name really, "Hypersonic". These guys make "Killer" gaming machines. When I got my FX7 laptop it cost me a little over $5,000, but I got it FULLY loaded plus a 200 gig external hard drive. That was two years ago it should be fairly priced now. All I really know is whatever game comes out I can play it in the highest quality of graphics without lag, every time.

Did you miscount the number of zeros in this persons budget?

Well, for that low of a budget its almost better to get some Dell or something, especially if you need a monitor. If you do need a monitor though, thats going to cost you at least 150$ (LCD), so your not left with anything worth anything. Save up your money if you can.