To answer my own question :-P
the right margin in page set-up had been changed from 1.9cm to 7cm. I
changed it back to 1.9cm and problem with comment box now gone!

"Melissa" wrote:

When I insert a comment in one of my word doc, the margins do not expand to
fit the comment box. Instead, my comment box nowoverlaps with the doc text.
I changed the settings to display it on left and the left margin expanded to
fit it nicely but when I changed the setting back (to right), the box
overlaps again.

I never had this problem before and can't imagine what could've caused it.

Any help?