The Add/Remove Programs Panel in Windows 2000 depends on a number of components and registry entries to display correctly. Some programs, when installed or removed, may damage these components and cause the Add/Remove Programs Panel to display incorrectly or not at all.
Here are some of the errors that may appear if the panel is damaged:
An unexpected error occurred. Class not registered
Object doesn't support this property or method res://appwiz.cpl/default.hta
If you see either of these errors, chances are the problem involves the APPWIZ.CPL component, which is invoked by the panel. If this component is damaged or missing, you will get the above error, but what's more likely is that it's simply become unregistered. To fix this, fire up a command prompt by typing CMD, and at the command prompt type REGSVR32 APPWIZ.CPL.
If this doesn't work, check to see if the APPWIZ.CPL component is missing. If it is, try running SFC (System File Checker) with the /SCANNOW option (i.e., type SFC /SCANNOW). You may be asked to provide the Windows 2000 CD-ROM.
If this also doesn't work, you can run an in-place upgrade from the Windows 2000 CD-ROM -- insert the CD-ROM, and select "Upgrade to Windows 2000."
Serdar Yegulalp is the editor of the Windows 2000 Power Users Newsletter.
This was first published in May 2002