problem getting into xp

My friend is having some problem with his computer right now. He said that his computer started to slow down alot and then he shut it down for a couple of minutes. After that, he tried logging back into xp and typed his password and stuff but once he typed that in and pressed enter, the computer froze at loading default settings or something like that. He tried this 3 times already and i haven't come up with a conclusion yet for the problem. Could you guys help me out? Thanks.

I had a problem where explorer.exe was corrupt. Try replacing it through the recovery console. It worked for me.