10 Use Trial

Hi all. I am trying to put a 15 uses trial on my application.
The following is my code I am using...:

Private Sub frmmain_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        Label3.Text = My.Settings.Trial
        If My.Settings.Trial = "0" = True Then
            Label3.Text = "This Trial has expired. Please Purchase Product Key"
            Button1.Enabled = False
        End If
        If My.Settings.TrialD = "Yes" = True Then
            Form2.Show()
            Me.Close()
        End If
    End Sub

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        If My.Settings.Trial = "0" = True Then
            Button1.Enabled = False
        Else
            My.Settings.Trial -= 1
            My.Settings.Save()
            Form2.Show()
        End If
        Label3.Text = My.Settings.Trial
        Me.Close()
    End Sub

    Private Sub Button4_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button4.Click
        If TextBox1.Text = "A-Number" = True Then
            My.Settings.TrialD = "Yes"
            Form2.Show()
            Me.Close()
        End If
    End Sub

    Private Sub Button3_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button3.Click
        PurchaseKey.Show()
        PurchaseKey.Opacity = 1
        PurchaseKey.Height.Equals(Me.Height)
        PurchaseKey.Width.Equals(Me.Width)
        PurchaseKey.SetDesktopLocation(Me.DesktopLocation.X(), Me.DesktopLocation.Y())
        Me.Close()

    End Sub

    Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
        Me.Close()

    End Sub

But when I debug it, and enter the Product Key to test if it activates, it does not seem to do so. When I stop Debugging it, the activation screen still comes up, when it is not supposed to. Can Anyone help me please?