Public Class Form1
    Public bstop As Boolean = False
 
    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As _
      System.EventArgs) Handles Button1.Click
        For i = 1 To 15000
            If bstop = True Then Exit For
        Next
 
    End Sub
 
    Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As _
      System.EventArgs) Handles Button2.Click
        bstop = True
    End Sub
 
 
End Class