Problem: After uninstalling a product using Microsoft's Windows installer (by running the *.msi file), it is discovered that all of the product's files are still present when they should have been deleted.
Cause: Hidden registry entries make the installer think another product is still installed and using these files. (This other "product" is probably an earlier version of your product which was uninstalled incorrectly.)
We uninstalled Kappris and deleted the program folder. We then followed the process in the article that Brian posted
The actual commands used were:
reg.exe query HKLM\Software\Microsoft\Windows\CurrentVersion\Installer\UserData /d /s /f "kutana\kappris\*" > reg_draft_cmd.txt
This creates a list of orphaned references in a text file.
findstr /C:"UserData" reg_draft_cmd.txt > reg_cmd.cmd
This creates a batch file listing the registry entries.
We edited each entry so it was similar to this:
reg.exe delete HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Installer\UserData\S-1-5-18\Components\05B5572B56228C740B47B36BC247F5C4
Running the batch file then deleted the registry entries.