button who turn next pages on the web - how to make that work???

Hello. I have a 99% working code. It's one problem. When i press button 3 it dosen't change site over and over agin.

It changes site to nummber 1, but no more.
The problem is that b has no value. But the code "b = b + 1" makes [B]b/B] get value 1. But later when i press the button 3, im still on the site 1. The b can only got value 1.

How do I save the value in b så b = b + 1 can be 2 or more.

Code:

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Private Sub Button3_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button3.Click
        Dim changesSE(2) As String
        Dim changesUS(2) As String
        Dim b As Integer
        Dim dtCurrent As System.DateTime
        Dim tdCurrent As System.DateTime
        Dim iMin As Integer
        Dim iHour As Integer

        ' time
        dtCurrent = dtCurrent.Now()
        tdCurrent = tdCurrent.Now()
        iMin = tdCurrent.Minute
        iHour = dtCurrent.Hour

        ' companys
        changesSE(0) = "www.google.se"
        changesSE(1) = "www.jesper.nu"
        changesSE(2) = "www.ubuntu-se.org"

        changesUS(0) = "www.microsoft.com"
        changesUS(1) = "www.youtube.com"
        changesUS(2) = "www.hotmail.com"

        If (iHour >= 9) And (iHour <= 17) And (iMin < 30) Then
            b = b + 1
            WebBrowser1.Navigate(changesSE(b))
            If (b = 24) Then
                b = 0
            Else
                b = b
            End If

        ElseIf (iHour >= 9) And (iHour <= 17) And (iMin > 30) Then
            b = b + 1
            WebBrowser1.Navigate(changesSE(b))
            If (b = 24) Then
                b = 0
            Else
                b = b
            End If

        ElseIf (iHour >= 17) And (iMin >= 30) And (iHour <= 21) Then
            b = b + 1
            WebBrowser1.Navigate(changesUS(b))
            If (b = 24) Then
                b = 0
            Else
                b = b
            End If

        ElseIf (iHour >= 17) And (iMin <= 30) And (iHour <= 21) Then
            b = b + 1
            WebBrowser1.Navigate(changesUS(b))
            If (b = 24) Then
                b = 0
            Else
                b = b
            End If

        ElseIf (iHour = 21) And (iMin > 30) Then
            b = 0                                    ' set b as value 0
            System.Threading.Thread.Sleep(39750000) ' sleep untill kl 9.00

        End If

    End Sub

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