There was a virus that did something similar a few years
back, but I can't remember the name (FYI only, I guess).

One quick thing to check is in your File->Open dialog
box.  Is your files of type set to "recover text from any
file"?  If so, change to Word Documents.

Also, what program opens when you double-click the
document, Word or Wordpad?  Maybe there's just an
association problem.  To reassociate .doc's with Word,
single-click on the file (or any .doc); then right-click
on it and choose "Open With"; select Microsoft Word and
select always use this program and hit OK (or other
procedures depending on your version of Windows).

HTH!

Dave