Public Class Form1
    Private Sub ComboBox1_SelectedIndexChanged(sender As Object, e As EventArgs) Handles ComboBox1.SelectedIndexChanged

    End Sub

    Private Sub ComboBox1_MouseClick(sender As Object, e As MouseEventArgs) Handles ComboBox1.MouseClick
        Timer1.Enabled = True
    End Sub

    Private Sub Timer1_Tick(sender As Object, e As EventArgs) Handles Timer1.Tick
        ComboBox1.Visible = False
        ComboBox1.Visible = True
        Timer1.Enabled = False
    End Sub

    Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
        Form2.Show()
        Me.Enabled = False
    End Sub
End Class





















Public Class Form2
    Dim var As Integer = 10
    Private Sub Form2_Load(sender As Object, e As EventArgs) Handles MyBase.Load
        Timer1.Enabled = True
    End Sub

    Private Sub Timer1_Tick(sender As Object, e As EventArgs) Handles Timer1.Tick
        var = var - 1
        Label1.Text = "Alert will be sent in " + var.ToString() + " seconds unless you Cancel"
    End Sub
End Class










Program(compiled in debug mode http://www.mediafire.com/file/gom2yy6zcoy7cxx/Ohh.exe )