C#

 private int x,y;<br />
 bool click=false;<br />
 bool first=false;<br />
 private void Form1_MouseMove(object sender,System.Windows.Forms.MouseEventArgs e)<br />
 {<br />
   if(e.Button==MouseButtons.Left)<br />
   {<br />
	if(click&&first)<br />
           this.Location=new Point(this.Location.X+e.X-    x,this.Location.Y+e.Y-y);<br />
	x=e.X;<br />
	y=e.Y;<br />
	click=true;<br />
	first=!first;<br />
	}<br />
	else<br />
  	click=false;<br />
<br />
	}<br />
<br />
	private void Form1_Load(object sender,   System.EventArgs e)<br />
	{<br />
	x=this.Location.X;<br />
	y=this.Location.Y;<br />
	}

protected override void WndProc(ref Message m)
{
	if (m.Msg == 0x0084)
		m.Result = (IntPtr)2;
	base.WndProc(ref m);
}