Mail Format tab

I?ve had this strange behavior in my Outlook 2003 for some time and cannot resolve it. I have repaired, uninstalled and reinstalled three times and updated services packs and such on my Outlook 2003 to no avail. I can click on the buttons (Internet Format?, International Options?, etc.) without issue. However, when I select any drop down box, Outlook freezes and then errors with a Send Report. I am unable to add/change my signature or the message format. When I install this copy on a test computer the behavior does not present itself, it runs fine. (I have since uninstalled this copy from the test computer). Does anyone have any advice on some corrective action as nothing has been effective in resolving my issue. I even tried replacing the comctl.dll file but that accomplished nothing.