This code  examines a sales order on sheet1  to determine which package to
un-hide on sheet13. Sheet13 is a purchase order and the start and end  of
each package is marked with a tag in the first column, i.e. <1lane> and
</1lane> for the start and end respectively of that package. The code hides
all the lines for packages that are not ordered, and un-hides the lines for
the ordered package, i.e. everything between stag and etag.

At first I thought it was the whole trying to examine data in hidden  rows
thing, so I tried manually un-hiding all of the rows and running  it, still
slow. If I hide all of them, save the workbook, close  Excel and then reopen
the workbook, even with the rows hidden it runs in just a few seconds the
first time, but slows down after that. This exercise was to rule out the
possibility that the hidden rows were causing the issue.