From your description it does sound as if zoom could be an issue. Note
that zoom can be different for Normal and Print Layout views. But, of
course, you would be able to see this by looking in the Zoom box on
the Standard toolbar...

If the problem is exclusively with new documents, you could try to
rename the blank document template (normal.dot) and have Word create a
fresh version of it.

You can find a description in the section titled "The simplest fix:
cleaning
up Normal.dot" in the article at
http://word.mvps.org/FAQs/AppErrors/BlankDocNotBlank.htm.