VBA to clear contents of a specific cell when opening workbook

Hi,

I am trying to get VBA to clear the content of a cell when I open the workbook but keep getting Run-time error '1004' Method 'Sheets' of object_Global failed.

I am using sub as below:

Sub Macro4()

Sheets("1 Pager").Select
Range("Z1").Select
Selection.ClearContents
Range("B7:J7").Select

End Sub

and then calling it in the Workbook_Open routine in the ThisWorkbook Window as below:

Private Sub Workbook_Open()

Call Macro4

End Sub

Any help, I am a VBA novice.

Thanks,

Rob