Private Sub Form1_KeyDown(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyEventArgs) Handles Me.KeyDownOn Error GoTo errorhandler 'this links it to an error handler - if you dont have one try "on error resume next" 
If keycode = keys.F12 Then  
button1_click 'where button1 is your start button 
else: 
exit sub 
end if 
end sub

Public Class Form1 
    Private Sub Start_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Start.Click 
        Timer1.Interval = FirstDelay.Text 
        Timer1.Enabled = True 
    End Sub 
    Private Sub Timer1_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Timer1.Tick 
        Dim generator As New Random 
        Dim randomValue As Integer 
        randomValue = generator.Next(0, 1000) 
 
        ShowDelay.Text = (Delay.Text + randomValue) 
 
        Timer1.Interval = (Delay.Text + randomValue) 
        System.Windows.Forms.SendKeys.Send(Text1.Text) 
        System.Windows.Forms.SendKeys.Send("{enter}") 
    End Sub 
    Private Sub Halt_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Halt.Click 
        Timer1.Enabled = False 
    End Sub 
    Private Sub Form1_KeyDown(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyEventArgs) Handles Me.KeyDownOn 
        On Error Resume Next 
        If keycode = Keys.F12 Then 
            Start_Click() 
        Else 
            Exit Sub 
        End If 
    End Sub 
End Class