This is from Kelly's Korner:
Add and Remove -Removing Invalid Entries in the Add/Remove Programs Tool
Start/Run/Regedit
HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Uninstall
Each program listed in Add/Remove Programs has a subkey listed here. Locate
the correct subkey for the program in question and right click it, then
select Delete. You may want to choose Export, first, to export the key to a
REG file. The REG file can be re-imported if you find you made a mistake.
You may have to contact the manufacturer of the program that you want to
remove if you need to clean up the disk and registry entries. The procedure
described in this section does not remove all the files and registry entries
used by the program; it removes only the reference in the Add/Remove
Programs tool.
Note: Other checkpoints to consider when trying to remove a program:
Check to see if the software/program is listed here: Start/Run/Regedit
HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
1. Right click the Program's shortcut/Properties to gain the Target Path.
2. Go to Start/Run/Msconfig/Startup and make sure it is not listed or
checked there. If so, uncheck it and remove the program listing from here:
Start/Run/Regedit
For items that were in the Start menu, Programs, Startup folder:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Shared Tools\MSConfig\startupfolder.
You'll find a subkey for each disabled item.
For items loaded from the Registry:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Shared Tools\MSConfig\startupreg.
Again, you'll find a subkey for each disabled item.
3. Go to Windows Explorer/Tools/Folder Options/File Types. If the program
file type is listed, either use Change or Delete.
4. Go to Start/Run/Regedit and navigate to this key:
HKEY_CLASSES_ROOT\Applications. If the program is listed, right click,
delete.
5. Go to Start/Run/Regedit and navigate to these keys:
HKEY_CURRENT_USER\Software and HKEY_LOCAL_MACHINE\SOFTWARE. If the program
is listed, right click, delete.
6. Go to Start/Run/Regedit. Edit/Find and under Find What type in the
program path gained from step one. From there either use Find next or F3.
7. Removing Invalid Entries in the Add/Remove Programs Tool
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall
You Cannot Reinstall a Program with the Add/Remove Programs Tool
