Option Explicit
Private Sub Worksheet_Change(ByVal Target As Range)
If Intersect(Target, [A1:A50]) Is Nothing Then Exit Sub
If Target.Value = 0 Then
Target.Interior.Color = RGB(0, 255, 0)
ElseIf Target.Value And Target.Offset(0, 1) = Target.Value Then
Target.Interior.Color = RGB(255, 153, 0)
'ElseIf ... Then ...
End If
End Sub