First here is the macro:

Private Sub Worksheet_Change(ByVal Target As Range)
If Intersect(Target, Range("A1")) Is Nothing Then Exit Sub
Application.EnableEvents = False
If Target.Value = "" Then
    Range("$S$1:$S$85").AutoFilter Field:=1
Else
    Call Macro1(Target.Value)
End If
Target.Select
Application.EnableEvents = True
End Sub

Because it is worksheet code, it is very easy to install and automatic to use:

1. right-click the tab name near the bottom of the Excel window
2. select View Code - this brings up a VBE window
3. paste the stuff in and close the VBE window

If you have any concerns, first try it on a trial worksheet.

If you save the workbook, the macro will be saved with it.


To remove the macro:

1. bring up the VBE windows as above
2. clear the code out
3. close the VBE window

To learn more about macros in general, see:

http://www.mvps.org/dmcritchie/excel/getstarted.htm

To learn more about Event Macros (worksheet code), see:

http://www.mvps.org/dmcritchie/excel/event.htm

Macros must be enabled for this to work!