Broken Windows Installer

Found a good post that helped when a "Windows Installer" application did not get removed correctly from the Control Panel, and I could not install the new version:

http://labnol.blogspot.com/2007/06/windows-installer-issue-when-programs.html

Bottom line was to run:

MsiExec.exe /I installer.msi REINSTALLMODE=voums REINSTALL=ALL

The article above also mentions the need to extract the files. I suppose that if you have a "setup.exe" file, there must be some method to extract the .msi file from it.