Go to support.microsoft.com and search for Article #290301
OFFXP: Windows Installer CleanUp Utility
This is a Clean Up utility for Office XP. HOWEVER, I am still suspicious that this might be virus related.
Exhaust all of the recent virus alerts at Microsoft, make sure whatever software you use for Virus protection that you have the most recent updates and search for any detection tools they may offer for recent virus such as msblast.exe. If you search your windows/system32 directory and find this, its the virus, its the cause.
Follow all of the information available for detecting and removing this bug and a half.
If it is not virus related, run this clean up utility per the instructions in the document adn then reinstall. If that does not correct the problem then I'm sorry, I have no other suggestions.
Hope this helps!!!!
LadyCK3