Public Class Form1

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        Timer1.Start()
    End Sub

    Private Sub Timer1_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Timer1.Tick
        If ProgressBar1.Value = 100 Then
            ProgressBar1.Value = 0
        End If
        ProgressBar1.Value = ProgressBar1.Value + 1
    End Sub

    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        ProgressBar1.Maximum = 100
        ProgressBar1.Minimum = 0
        ProgressBar1.Value = 0
    End Sub

    Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
        Timer1.Stop()
    End Sub
End Class