So you want to compare two documents in Microsoft Word.  This works
best if the two files are very similar, e.g. file1.doc was saved at
some point, and then someone came in and made a few modifications here
and there, maybe adding new sections, removing others, and modifying
things.

In these example instructions, you've got the original saved as
file1.doc, and the edited version in file2.doc.

On a computer running Windows with Microsoft Word 2003:

+ Open file2.doc in Word.

+ Choose Tools -> Compare and Merge Documents...  Find and select
  file1.doc.  Click the Merge button.

+ In a few seconds, a new document window should appear.  This is a
  'merged' version of the two documents.  Text added to file2.doc that
  was not in file1.doc should show up as red.  Text that was in
  file1.doc that has been removed from file2.doc should show up as
  blue.  You should also be able to click the 'Next' button on the
  Reviewing toolbar to jump directly from change to change, without
  having to visually scan for all of them.

On a Mac running Microsoft Word 2004 for Mac:

+ Open file2.doc in Word.

+ Choose Tools -> Track Changes -> Compare Documents...  Select and
  open file1.doc.

+ New text will be red.  Old text will show up in 'word balloons' in
  the right margin.  Clicking the Next button in the Reviewing toolbar
  should work as above.