Hi
I'm not sure if you can hide a select range of data though you can hide formulas. You may, however, hide complete rows or columns.
This little procedure will hide columns B & C if the value in A1 is false and show the columns if the value in A1 is true.
Right-Click on your worksheet tab choose "view code", and paste the following as is:
<pre>
Private Sub Worksheet_Change(ByVal Target As Range)
If Not TypeName([A1].Value) = "Boolean" Then _
Exit Sub Else: Columns("B:C").EntireColumn.Hidden = Not [A1].Value
End Sub
</pre>
Tom