protected override void ProcessRecord() { if (hWnd == IntPtr.Zero) { hWnd = System.Diagnostics.Process.GetCurrentProcess().MainWindowHandle; } IntPtr hMenu = USER32.GetSystemMenu(hWnd, false); USER32.EnableMenuItem(hMenu, USER32.SC_CLOSE, USER32.MF_GRAYED); // Disables controlbox USER32.RemoveMenu(hMenu, USER32.SC_CLOSE, USER32.MF_BYCOMMAND); // Disables the exit menu }