This sounds like the klez worm. The following article talks about Word 2002,
but klez affects 2000 as well:

http://support.microsoft.com/?scid=kb;en-us;323037

--
Herb Tyson MS MVP
Please respond in the newsgroups so everyone can follow along.
http://www.herbtyson.com
"DebL" wrote in message
...
This morning I tried to open a document that I've accessed many times with
no
trouble. However, this time it said that a feature was missing and I
needed
to insert my 2000 Small Business CD. I did so, but now the document is
just
a bunch of little squares. All my text is gone. Other documents in the
same
folder are doing the same thing, but not all of them.

Any ideas what is causing this and how I can fix it?