With Sheets("tableau")
For i = 1 To .Range("H1200").End(xlUp).Row
If ComboBox2.Value = .Cells(i, 3).Value Then
userform2.Show
Exit For
End If
Next i
End With
[COLOR=green]'ou alors avec un Find[/COLOR]
With Sheets("tableau").Range("H3:H1200")
' on cherche l'adresse de la cellule contenant la valeur de la combo
Set c = .Cells.Find(ComboBox2.Value, LookIn:=xlValues)
If Not c Is Nothing Then
userform2.Show
End If
End With