Excel 2003 loses Customization of toolbars
 

I have a user with a new install of Office 2003 and he has customized his
Excel 2003 toolbars with standard Excel Icons. The tool bar will revert to
the default settings at random times during the day while he is using it. I
have tried to re-register Excel and searched through the Google groups for
assistance and tried the solutions posted which include making a backup copy
of the *.XLB file. The problem is that the tool bars will change while he is
using it. Any help would be appreciated as none of my other users are
experiencing this issue and the user that is ---- is my boss.