$21 and your problem is solved.. looks like it even has a power supply and usb ports.
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewI...3&category=3669
Or if you want to find another one.. here is a shortcut to relevant results.
http://search.ebay.com/search/search.dll?q...10&BasicSearch=
I've had friends that just had their computers in a pile of hardware sitting off to one side. Get a box they don't cost much.. not sure where you live but there should be an electronics discount place near by. Its cheaper to buy a case than it is to try and build something.. as long as that something isn't made out of cardboard. haha