comparison macro

Thanks, that was a bit of a numb skull question which I shot off before thinking about.

Thanks for all your help, the macro works very well and now gets rid of discrepancies that have been causing problems in the past.

Is it possible to add this macro to work at the end of a previous macro action
ie. I now have a macro that I recorded to copy and past a sheet then take out some columns before I run the macro that you wrote, can these two be easily combined? The only way i can do it currently is to add some recorded code that selects your macro and runs it, e.g.
Application.Run "'Milestone281008v2.xls'!Highlight"
but this stops working as soon as I change the workbook (Milestone281008v2.xls) name.

Here is what I run before your one:

COMP1 Macro
' pre highlight macro
'

'
Sheets("Milestone").Select
    Cells.Select
    Selection.Copy
    Sheets("mine").Select
    Cells.Select
    Selection.PasteSpecial Paste:=xlValues, Operation:=xlNone, SkipBlanks:= _
        False, Transpose:=False
    Selection.PasteSpecial Paste:=xlFormats, Operation:=xlNone, SkipBlanks:= _
        False, Transpose:=False
Sheets("mine").Select
    ActiveSheet.Outline.ShowLevels RowLevels:=0, ColumnLevels:=2
    ActiveWindow.ScrollColumn = 17
    Columns("AA:AA").Select
    Selection.Delete Shift:=xlToLeft
    Columns("AC:AE").Select
    Selection.Delete Shift:=xlToLeft
    Columns("AE:AL").Select
    Selection.Delete Shift:=xlToLeft
    Columns("AH:AI").Select
    Selection.Delete Shift:=xlToLeft
    Columns("AJ:AJ").Select
    Selection.Delete Shift:=xlToLeft
    ActiveWindow.ScrollColumn = 36
    Columns("AP:AW").Select
    Selection.Delete Shift:=xlToLeft
    ActiveWindow.ScrollColumn = 45
    Columns("A:AY").Select

Thanks again mdbct!

B.