using System.Runtime.InteropServices; [DllImport("User32.dll")] public static extern bool LockWorkStation(); [DllImport("User32.dll")] private static extern bool GetLastInputInfo(ref LASTINPUTINFO plii); [DllImport("Kernel32.dll")] private static extern uint GetLastError(); private struct LASTINPUTINFO { public uint cbSize; public uint dwTime; } private void Form1_Load(object ..