Option Explicit
Private Sub Worksheet_Change(ByVal c As Range)
Dim plage As Range
Set plage = Range("B:B,D:D,F:F,G:G")
If c.Count > 1 Then Exit Sub
If Not Intersect(c, plage) Is Nothing Then
Select Case c
Case Is <> "": c.Interior.ColorIndex = 4: Case Else: c.Interior.ColorIndex = xlNone
End Select
End If
End Sub