Set up a workbook as you want it (number of sheets, cell formats etc) and
turn on gridlines in Page Setup.
Now Save As, and change the file type to "Excel Template (.xlt)" not (.xls).
Locate your XLStart folder, typically somewhere like "c:\documents and
settings\username\application data\microsoft\excel\xlstart\" and save the
file as "book.xlt"

Every time you open a new workbook from now on (you may have to restart
Excel first) this template will be used - including the gridline settings.
To revert back to the original, just delete this file.

Paul C,