Zeokage

I'm an idiot. I spent all this time trying to get my uncle to find his XP discs in order to do this check, and totally forgot to search on the method in case it didn't need the discs.

Holding Delete on turning on the computer seems to have done something, it's managed to get past the unmountable boot volume stage and is doing a chkdsk right now. The volume is apparently dirty.

...and now it seems to be working. Thanks for the help, even if it took me months to actually follow through on it.