I’ve figured out a way to tell which version of the .NET framework is installed by reading previous SO posts, but I’ve not found anything about the Windows Installer.
Is there a registry key or anything similar that I could verify that Windows Installer 3.01+ is installed?
“If you want to check the version of the Windows Installer on your system, check the version of MSI.DLL in the Windows\System 32 folder”
http://blogs.msdn.com/windows_installer_team/archive/2005/08/05/448386.aspx