Option Explicit
Private Sub Worksheet_Change(ByVal Target As Range)
Dim L As Long, P As Range, C As Range
L = Target.Row
If Application.CountA(Rows(L)) = 0 Then Exit Sub
Set P = Range("A" & L & ":F" & L)
If Application.CountBlank(P) > 0 Then
For Each C In P
If C = "" Then
C.Interior.ColorIndex = 3
Do
C = InputBox("Donnée à saisir", "Attention,")
Loop Until C <> ""
Else
P.Interior.ColorIndex = xlNone
End If
Next
End If
Cells(L + 1, 1).Select
End Sub