[CentOS] Centos5 and X respawning problem

[DamianS]

Ouch! I hope you are charging $150/hr to fix the laptop of this clueless
user?

Have you looked in the system logs to see what errors are being written?

This error message has several causes, some of which can be easy to
track down - others not.
You could spend the time tracking the cause down, but I suspect you will
find more than 1 problem, since you have no idea what this idiot has
done to the system.
One idea from left field is they might have modified the security
settings and PAM is kicking the user out before it can login.

So I recommend instead, you simply wipe the sytem and reinstall CentOS5,
and tell the user not to touch anything they don't know about.