Private Sub Workbook_Open()
'SOURCE:http://www.excel-downloads.com/forum/27955-se-postionner-sur-semaine-en-cours-en-vba.html
'auteur: omicron
'On Error GoTo ExistePas
'Sheets("Sem" & Format(Now, "ww")).Activate
'On Error GoTo 0
'Exit Sub
'ExistePas: MsgBox "La feuille " & "Sem" & Format(Now, "ww") & " n'existe pas." & Chr(10) & _
'"Positionnement impossible."
'adaptation staple
Dim NS As Long
Dim SD As Long
On Error GoTo ExistePas
Application.DisplayAlerts = False
NS = Format(Now, "ww")
SD = NS - 1
Sheets("Sem " & SD).Delete
On Error GoTo 0
Exit Sub
ExistePas: MsgBox "La feuille " & "Sem " & SD & " n'existe pas." & Chr(10) & _
"Positionnement impossible."
End Sub