Check for .Net availability

If one tries to start a .net application without the .net framework installed, one will get a nasty error message. I'd like to be able to use some true win32 code that will fire before the actual .net code which will present the user with an error message stating the reason for not starting. I've looked around a bit, but I can't find any code readily available. Does anyone know if there is something like this anywhere? If not, I'll have some digging to do, as my experience with win32 code is severely limited :( Jesse