>Any suggestions on what to check to see if .Net is installed and what version of the CLR is available for unmanaged applications calling into .Net via COM interop?
>
>Been looking through the registry and other than some specific keys that can be hacked into parts there seems to be no place where the .Net is officially logged as installed.
>
>Any suggestions?


Start with registry:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\.NETFramework\InstallRoot

And from the location found under this key, list the folders.
The folders names was the framework versions installed on the computer...

I have WIN2K, I dont know if the key was the same for other OS.