Kindly Check What Is Wrong In Checking An Excel File Open Or Not

halloo everybody
Here is my code to check an excel sheet wether it is open or not.
It is working good in the following situations.

1.if the excel file is not yet opened. then it is opening and bringing a value from some cell of the sheet1.
2.If the file is already opened and not yet closed. it is not opening again it is understanding that the file is already openrd and bringing the cell value.
3.It is working when it is closed by the user and again clicked the button to open. It is opening and bringing the value.
4.NOW the problem starts.
IT IS NOT WORKING , If I click the button again to open. It is opening another copy of the same file. I did't understand why is it working perfectly? before I close the file and not working if I close the File.

please kindly check my code and respond to me .
here is my code but it is not working when the file is already opened.


Private sub Cmd_Click()

Dim XL As New Excel.Application
Dim wbk As New Excel.Workbook
Dim ws As New Excel.Worksheet


WorkBookName = "Book2.xls"
If Not WorkbookOpen(WorkBookName) Then
chk = 1
Set wbk = XL.Workbooks.Open("C:Dokumente und EinstellungenKiran KarnatiDesktopEXCELBook2.xls")
Else
Set wbk = Workbooks(WorkBookName)
End If

Set ws = wbk.Worksheets("Sheet1")
If chk = 0 Then
With ws
Label48.Caption = .Cells(1, 2).Value
.Cells(1, 3).Select
End With
Else
With ws
Text49.Value = .Cells(1, 2).Value
End With
End If
XL.Visible = True

Set SA = Nothing
Set XL = Nothing
Set wbk = Nothing
End Sub
_________________________________________________


Function WorkbookOpen(WorkBookName As String) As Boolean
'Returns TRUE if the workbook is open
WorkbookOpen = False
On Error GoTo WorkBookNotOpen
If Len(Excel.Workbooks(WorkBookName).Name) > 0 Then
WorkbookOpen = True
Exit Function
End If

WorkBookNotOpen:
End Function

Thank you.
Kiran.