lol, first off, you wanna check out deals on parts....you know with rebates.
heres the best sites i like:
Second, you prob wanna go with:
Amd64 sempron processor...more cost effective
80gb ide hard drive
motherboard-Good brands include Asus, epox, gigabyte, etc..(check out newegg.com reviews and look at peoples builds...usually in their signature)prob dont wanna spend more than 60 bux here.
get 512mb-1gb ram
simple vid card and vwalla...(i like ati vid cards)
for 500 bux your cutting it slim, and you did not mention if you were a gamer or what not?
PS: I dont include the price of windows xp because you can get it as a student for cheap or you can use LINUX : )
Some easy to use distro's are PClinuxOS, Linspire, SimplyMepis, and Xandros3.0, although PCLINUXOS is prob the best choice...its free and easy to use!! and with linux you dont get all those stupid viruses, spyware, and crap that you get with windows!!!!!!!
plus if you want office programs, you can get a program called open office just like ms office but FREE!! save you money..unless you download them from free bittorent files!! lol.