Good stuff, thanks!
I eventually ended up with this simple code:
SetError(0)
RegRead("HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\NET Framework Setup\NDP\v3.5\","Install")
If @error <> 0 Then
MsgBox(0,"Info", ".NET v3.5 or higher is required!")
EndIf
As it turns out this key will always be present if v3.5 is installed. Also, .NET installs prior versions during the installation process of any version, so if a higher version of .NET is installed, this key will definitely be found.
I have done the same to see if there is a PDF viewer installed on the machine:
SetError(0)
RegRead("HKEY_CLASSES_ROOT\.pdf","")
If @error <> 0 Then
MsgBox(0,"Info", "A pdf reader is required.")
EndIf
Thanks all for your swift and helpful replies!
Ascend4nt - I found your code sample very useful for other things too