When you develope installer packages, you might face the situation where you install you product for testing purposes but cannot uninstall it because the uninstall mode is not ready, yet. Mircorosft used to offer a tool called Windows Installer Cleanup Utility than removed all file sytsme and registry items added during setup process without needing the actual installer.
Unfortunately, Mirosoft has disconstinued this utility. Fortunately, others still offer the tool for download. For example:
Warning: this tool might get your registry messed up. Be prepared to get into trouble when using it.