How do I detect what .NET Framework versions and service packs are installed?

Question

A similar question was asked here, but it was specific to .NET 3.5. Specifically, I\'m looking for the following:

1. What is the correct way to determine which .N

Answer 1

Enumerate the subkeys of HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\NET Framework Setup\NDP. Each subkey is a .NET version. It should have Install=1 value if it's present on the machine, an SP value that shows the service pack and an MSI=1 value if it was installed using an MSI. (.NET 2.0 on Windows Vista doesn't have the last one for example, as it is part of the OS.)