Add/Remove Programs doesn't work

This is a repeat of my earlier question. The Add/remove program feature doesn't work in Windows2000.
Error:
"Object doesn't support this property or method rez://appwiz.cpl/default.hta
Line 75"
Before the question was submitted, the virus software had been updated, system scanned for viruses with other virus software as well as McAfee 6.0, which is installed. No viruses have been found. Virus software has been uninstalled,(by Mcafee), and reinstalled. Nothing has affected the problem.
Please try again. I would have preferred to contact the person who responded the first time but could't find how to do so ..so a repeat of the question! I even checked the registry for all the entries that affect the add/remove programs feature.. (See Q266668 from Microsoft.) I don't want to reinstall the OS unless I know what caused the trouble and get it fixed!