>I want to be able to start an application based on a given file extension. Can some one tell me if there is an API function that will return the associated exe name if I pass it an extension. Also, if there is not an associated exe then I want to be able to open the "Open With" dialog so the user can set up a file extension to exe association.

Sorry Dennis, I forgot to tell you the rest. The value returned, if it's greater than 31 is the instance handle, otherwise it's an error, If it's 31, no executable is associated with the file. If there is an executable associated with the file, you can start it using ShellExecute(). If you need details, let me know.