Run multiple winform instance sequentially

Maybe this can work:

public static bool IsProgramRunning(string TitleOfYourForm)
{
    bool result = false;
    Process[] processes = Process.GetProcesses();
    foreach (Process p in processes)
    {
         if (p.MainWindowTitle.Contains(TitleOfYourForm))
         {
             result = true;
             break;
         }
    }
    return result;
}

Call this function in the Main function(before opening the mainForm), if it is false Application.Exit() else show your form..
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