Macro for changing number of rows

try recording a macro it will give you some ideas.
the one above by shg looks like this when recorded

Sub Macro3()
'
' Macro3 Macro
' Macro recorded 01/04/2010 by martin
'

'
    Columns("A:C").Select
    Selection.Sort Key1:=Range("B2"), Order1:=xlDescending, Key2:=Range("C2") _
        , Order2:=xlDescending, Header:=xlGuess, OrderCustom:=1, MatchCase:= _
        False, Orientation:=xlTopToBottom
End Sub

you can then change the selection bit

Columns("A:C").Select
    Selection.Sort Key1

to

Columns("A:C").Sort Key1