Private Sub Button1_KeyDown _
      (ByVal sender As Object, ByVal e As System.Windows.Forms.KeyEventArgs) _
         Handles Button1.KeyDown
        Blink(CType(sender, Button))
    End Sub
 
    Private Sub Button1_MouseDown(ByVal sender As Object, _
    ByVal e As System.Windows.Forms.MouseEventArgs) _
        Handles Button1.MouseDown
        Blink(CType(sender, Button))
    End Sub
 
    Private Sub Blink(ByVal btn As Button)
        With btn
            Dim bc As System.Drawing.Color = .BackColor
            .BackColor = Color.Red
            .Refresh()
            Threading.Thread.Sleep(100)
            .BackColor = bc
            .Refresh() 
        End With
    End Sub