Detecting installed programs via registry

Question

I need to develop a process that will detect if the users computer has certain programs installed and if so, what version. I believe I will need a list with the registry loc

Answer 1

You could use MSI API to enumerate everything installed by Windows Installer but that won't list all the software available on a machine. Without knowing more about what you need I think the concept of "installed" is a little vague. There are many ways to deploy software to a system ranging from big complicated installers to ZIP files and everything in between.