If you take MegaTower's advice I would recommend going to Microsoft's download site http://www.microsoft.com/downloads/search.asp?
search by keyword and download the office eraser program just search for eraser it will give you 3 hits.
Eraser97 which is for the Office 97 install and 2 others, one for each office CD for Office 2000.
Do an uninstall then run this program It cleans the registry of all major entries for MS Office. Just running an uninstall does not get everything.
I would also download regclean. It cleans and compacts the registry. Do this last.
Here are the steps I'd take:
1) From add/remove programs uninstall office
2) Delete the MS Office directory (C:\Program Files\Microsoft Office (unless you installed it in aplace other than the default location))
3) Install and run the eraser program
4) uninstall the eraser program (make sure you delete the eraser program directory if it still exists after uninstall)
5) Run Regclean
6) Do a Scandisk
7) Do a Defrag
8) Reboot
9) Reinstall Office.
Before doing this you might want to check out Microsoft's KB to see if there is an answer there.
http://search.support.microsoft.com/kb/c.asp?fr=0&SD=GN&LN=EN-US