Q:

Hide columns if cell has a given value

I would like to hide some columns if A1 changes but I am afraid that the function Worksheet_Change does not work.
I have the following code but if I change A1 nothing happens.
Private Sub Worksheet_Change(ByVal Target As Range)
    If Target.Address = "A1" Then

        Call hideColumns()
        '
        '
    End If
End Sub

A:

change to 
If Target.Address = "$A$1" Then 

or maybe use (my favorite):
If Not Intersect(Target, Range("A1")) Is Nothing Then 

