TComboBox Access Violations Viewing Drop-Down List in D5-UP1

We are having frequent but unreproducable problems with TComboBox components
generating Access Violations when people try to view the drop down list.

When it happens, we tell the inflicted user to reboot, and the problem does
not occur for a while.

This problem started occurring as best as we could tell shortly after we
were upgraded from Office 97 SP2to Office2000 SP1 on Windows NT SP6a
compiled in either Delphi 5 Pro or Enterprise (Update Pack 1 on both).

Is there something that can be done or checked out to help alleviate the
problem?

(I did some searching on Google Groups, but could not find a concrete
solution to this type of problem.)

Thanks in Advance

Al Cantu