Sub Worksheet_Change(ByVal Target As Range)
If Target.Count > 1 Then Exit Sub
If Not Intersect(Target, Range("A2")) Is Nothing Then
If Target = "" Then
ActiveSheet.Range("$C$3:$D$100").AutoFilter Field:=1
Else
ActiveSheet.Range("$C$3:$D$100").AutoFilter Field:=1, Criteria1:="=" & Target, Operator:=xlAnd
End If
End If
End Sub