startbutton.cs

using System;
using System.Runtime.InteropServices;

class Test
{
    const uint KEYEVENTF_EXTENDEDKEY = 0x0001;
    const uint KEYEVENTF_KEYUP = 0x0002;
    const uint KEYEVENTF_UNICODE = 0x0004;
    const uint KEYEVENTF_SCANCODE = 0x0008;
    const byte VK_LWIN = 0x5B;

    [DllImport("user32.dll")]
    static extern void keybd_event(byte bVk, byte bScan, uint dwFlags, int dwExtraInfo);

    public static void Main(string[] args)
    {
        keybd_event(VK_LWIN, 0, 0, 0);
        keybd_event(VK_LWIN, 0, KEYEVENTF_KEYUP, 0);
    }
}