What grade rating was it ?? Usually something with that kind of damage would be "C" rated which is kind of a scratch and dent rating but even that shouldn't have a bunch of dust bunnies etc. - Glad to hear it is at least working, did the XP COA come with the case or are you putting on a copy you had already ?
I think it was B, but cant swear to it, and I don't see it on the receipt.
It had a XP product key sticker on it, but when it booted it said it couldn't find the OS, so I installed a XP copy I have.
It's a little slow, I think I have another stick of ram I can add to it, will probably speed it up. (has 256 meg now).
Mame and NES seems to run fine on it.