Chuck,
If you don't care what is associated with the extension you can just use ShellExecute() with the rtf file and let windows start the app. There's some examples on my website under Q&A, General.
>I make a RTF file and want to start-up the program who is associated with that program. I look into the win.ini and it doesn't have the RTF extension - I then looked though the Registry and saw some extension under "HKEY_LOCAL_MACHINE\SOFTWARE\MICROSOFT\WINDOWS\CURRENTVERSION\EXTENSIONS", but when I look in Explorer to see what ext. is related to what app. There is more that both the win.ini and the registry put together. Does any one know how to get an application that is associated to the extension?