Time VBA problem

[Toonies]

Hi and thanks for taking a look at this post

I have found this Time VBA

http://www.mrexcel.com/forum/showthread.php?t=81210

is it possibleto amended so that it ignores Text in Column B

Private Sub Worksheet_Change(ByVal Target As Range)
Dim UserInput, r&
Application.EnableEvents = False
If Not Intersect(Target, [B:C]) Is Nothing Then
    If Not Selection.Cells.Count = 1 Then
        Application.Undo
        Application.EnableEvents = True
        Exit Sub
    End If
    If Target.Value < 1 Then
        UserInput = Format(Int(Target.Value * 24) * 100 + ((Target.Value * 24) - Int(Target.Value * 24)) * 60, "0000")
    Else
        UserInput = Format(Target.Value, "0000")
    End If
    If Len(UserInput) > 1 Then
        Target = Left(UserInput, Len(UserInput) - 2) & ":" & Right(UserInput, 2)
    End If
    r = Target.Row
    If Cells(r, 2) = "" Or Cells(r, 3) = "" Then
        Cells(r, 4).ClearContents
    Else
        Cells(r, 4).FormulaR1C1 = "=MOD(RC[-1]-RC[-2],1)"
    End If
End If
Application.EnableEvents = True
End Sub