// Registering Notepad.exe as a collab application with a fixed GUID.
// Note: If you're using the application to send invitations,
// the same application with the same GUID must be registered on the remote peer machine.
private static PeerApplication RegisterCollabApp()
{
    PeerApplication application = null;
    string pathToApp = "%SystemRoot%\\notepad.exe";
    Guid appGuid = new Guid(0xAAAAAAAA, 0xFADE, 0xDEAF, 0xBE, 0xEF, 0xFF, 0xEE, 0xDD, 0xCC, 0xBB, 0xAE);

    application = new PeerApplication();
    application.Id = appGuid;
    application.Path = pathToApp;
    application.Description = "Peer Collaboration Sample -- notepad.exe";
    application.PeerScope = PeerScope.All;
    application.CommandLineArgs = "n";
    application.Data = ASCIIEncoding.ASCII.GetBytes("Test");

    Console.WriteLine("Attempting to register the application \"notepad.exe\"...");
    try
    {

        PeerApplicationCollection pac = PeerCollaboration.GetLocalRegisteredApplications(PeerApplicationRegistrationType.AllUsers);
        if (pac.Contains(application))
        {
            Console.WriteLine("The application is already registered on the peer.");
        }
        else
        {
            PeerCollaboration.RegisterApplication(application, PeerApplicationRegistrationType.AllUsers);
            Console.WriteLine("Application registration succeeded!");
        }
    }
    catch (ArgumentException argEx)
    {
        Console.WriteLine("The application was previously registered with the Peer Collaboration Infrastructure: {0}.", argEx.Message);
    }
    catch (PeerToPeerException p2pEx)
    {
        Console.WriteLine("The application failed to register with the Peer Collaboration Infrastructure: {0}", p2pEx.Message);
    }
    catch (Exception ex)
    {
        Console.WriteLine("An unexpected exception occurred when trying to register the application: {0}.", ex.Message);
    }
    return application;
}