Private Sub Workbook_SheetSelectionChange(ByVal Sh As Object, ByVal Target As Range)
If Range("B10").Value = 1 Then
Range("B10").Value = "Some other Value"
Range("B10").Select
MsgBox "Warning, Warning, Explosion Immminent", vbOKOnly + vbExclamation, "A helpful little box"
End If
End Sub