public maın1()
 {
     InitializeComponent();
     if (frm == null)
     {
         frm = this;
     }
     this.button2.Enabled = false;
     this.button3.Enabled = false;
     this.button4.Enabled = false;
     this.button5.Enabled = false;
     this.button6.Enabled = false;
     this.button7.Enabled = false;
 }
 static void frm_formClosed(object sender, FormClosedEventArgs e)
 {
     frm = null;
 }