what vesrsion of word are you using on the new computer?
my version is 2003
check out your tool bar options to add or remove buttons.
at the top of word you will see the current tool bars
at the end of each tool bar is a tiny upside down arrowhead with a bar over it
select add or remove buttons
select standard look for ZOOM
click zoom and a button will appear on your tool bar.
this will change the whole documnet to 75%
just use 9. ie 75% of 12 is 9.
you can select 9.5 if you want to... in >Format >Font> type the font size you want then select ok. Hilite a block of text if want to change something you ahve already written.