Option Explicit
Sub Tous_onglets_sauf_x()
Dim o As Object
Application.ScreenUpdating = False
For Each o In Worksheets
If o.Name <> "a" And o.Name <> "b" Then
o.Range("H7:I105,R7:S105,AP7:AQ105,AY7:AZ105,BW7:BX105,CG7:CH105").ClearContents
End If
Next
Application.ScreenUpdating = True
End Sub