Re: Windows Xp
nothing really, pretty standard these days.. $500 or less gets u a half-decent computer lately (if no monitor is needed)
core 2 (dual or quad) or i7 as processor,
2gig ram (more is better), but then usual usages only require this much
hard drives are more capacity the better, but try getting western digital BLUE drives or segate barracuda (Oem versions)
motherboards, stick to brand names like asus (100 to 150dollars)
dvd writers/re-writers/cdrom drives , anything thats standard/cheap. LG for example.
powersupply (part of big box, sometimes NOT part of big box). please ensure its like 400 to 600 watts. i have successfully ran 250watt powersupplies with 3 hard drives, a video card that had its own fan, 2 cd/dvd drives and an extra case fan, and mysteriously it worked until one day i realized thats a fall-apart situation waiting to happen.
case, sizes go in lying desktop, tower: small, mid and full. for average no-nonsense usage i recommend mid size tower. although, if u're only getting 1 hard drive, 1 cdrom drive, and selecting a motherboard that will let u have sound video and network from the motherboard itself (integrated motherboards, lately a GOOD affordable trend), then u can get a small tower.
if u will be doing some adding removing later on (one hard drive, expanded to another hard drive, or second cd drive added or dedicated new video card added or a video capturing card), then i recommend mid size case.
budget permitting, get a case with a "CASE FAN" installed and not "OPTIONAL/SUPPORTED/AVAILABLE".
keyboard, mouse, cd drive, and screens i usually recommend people to keep from their old machines if they're just thinking of starting a BRAND new box.. case, powersupply, motherboard, processor, ram, and hard drive i recommend getting new