Setting variables

I have a macro that when the file opens only works the first time, I am told that I need to set variables. Can anyone explain or show me what I need to do please.


Sub Macro1()

Application.EnableEvents = False
Application.DisplayAlerts = False
Application.ScreenUpdating = False
If Range("ap1").Value = "X" Then Exit Sub
Sheets("Sheet1").Select
Workbooks.Open Filename:="\\Ame-win2k\DriveE\MAL DATA\Projects\4 Database\Contract_DB_V1.1.xlsm" _
, UpdateLinks:=0, ReadOnly:=True
Sheets("Main").Select
Range("c8:Q2000").Select
Selection.Copy
Windows("Packing_Note_V1.1_12_Mar_2013.xlsm").Activate
Sheets("Sheet1").Select
Range("A8").Select
Selection.PasteSpecial Paste:=xlValues, Operation:=xlNone, SkipBlanks:= _
False, Transpose:=False
Range("table").Select
Selection.Sort Key1:=Range("a8"), Order1:=xlAscending, Header:=xlGuess, _
OrderCustom:=1, MatchCase:=False, Orientation:=xlTopToBottom
Windows("Contract_DB_V1.1.xlsm").Activate
ActiveWorkbook.Close savechanges:=False
Windows("Packing_Note_V1.1_12_Mar_2013.xlsm").Activate
Sheets("Site Label").Select
Range("a20").Select
Macro8
End Sub

Hi,
the main thing you can come unstuck on is using windows("workbookname")

try using this type to describe which workbook you are using
Workbooks("Book1").Worksheets("Sheet1")
however it is usually best to declare workbooks

ie

Dim wb1, wb2 as workbook
Dim WB2filename as string
WB2filename = "Contract_DB_V1.1.xlsm"
set wb1 = thisworkbook
set wb2 = workbooks(filename)

'then use wb1 or wb2
wb1.sheets("Sheet1").range("A8").select
' or
with wb2.sheets("Site Label")
    .Range("A20").seect
End with

heres a link to a site giving info about workbooks etc
http://www.techrepublic.com/blog/10t...-using-vba/967