x won't start as a particular user. for other users works fine. what file is causing it? how to troubleshoot?

[Mitchell Laks <mlaks@post.harvard.edu>]

Hi,

I am running sid on a laptop. X was working fine.

I lent my laptop to my sister for a few weeks and her kids played with it,
and she returned it saying "it doesn't work".

The problem is that X won't start as a single particular user. For all other users, X starts fine.

Additionally if I edit /etc/passwd  and change login location 
of that user to
/home/bob/temp
then X starts normally again.

I looked for .xinitrc .xsession files .xsession-error  files etc.

I looked in the /var/log/Xorg.0.log file and no information...

1. What file can be causing the problem?
2. What can I do to make X more verbose so I can find what error is causing X  not to start?

thanks
Mitchell Laks