You can do this by renaming Normal.dot, but see
http://word.mvps.org/FAQs/AppErrors/BlankDocNotBlank.htm for advice on
preserving customizations.
If all you need to change is the margins, then you can do this without
renaming Normal.dot. Open a new blank document. In Page Setup, without
making any other changes, set top and bottom margins to 1", sides to 1.25",
then click the Default... button and answer yes.
--
Suzanne S. Barnhill
Microsoft MVP (Word)
Words into Type
Fairhope, Alabama USA
http://word.mvps.org