[Only3]

this can easy done with process class and Environment.GetCommandLineArgs

[Only3]

Code

if (Args.Length < 2) {
    Process.Start(new ProcessStartInfo(Application.ExecutablePath, "1"));
} else if (Args(1) == "1") {
// New Instance
}

[Only3]

This would not work. Did you even try it?

This work. Did you even try it?

[Only3]

bahna open ur brain its easy to do it
also this way u not creating new files all in memory
tip use the power of the args to pass the info

[Only3]

to send arg back to the app u can use sendmessage api