I believe your password is case-sensitive...you could try that (I believe the short name has to be lowercase, with no spaces). I'm not sure about this, but I think you can use either your short name or your full name to log in under. But I would try several permutations with upper-case, lower-case, and initial caps. I think you're in trouble if you can't get authenticated though. With most Unix-like OSes, your only other option is a reinstall: there's no obvious way to back-door into the system without giving a valid password--which is a good thing!