I would suggest that you try to clean the CD.
The following information is from Leo Laporte:
"Contrary to popular belief, CDs are not indestructible. A scratch, a piece
of dirt, even a fingerprint can render them unplayable. In fact, a
deep-enough scratch on the printed side can harm data on the other side of
your CD, so treat them with care. If they do get a little dusty and dirty
and you're having a hard time playing them, you can clean them-- believe it
or not-- with soap and water. That's right, it's OK to get these wet.
"Use a mild detergent like dish soap, some warm water, and a clean cloth.
Here's the only real trick: When you scrub, do it from the center out in a
radial direction. That's contrary to the way we used to tell people to clean
their vinyl albums. You may remember that we used to clean them in a
circular motion. That's bad for CDs. If you get any scratches at all on the
surface, you want them to be across the data, not parallel to the data. So
always scrub from the center out.
"Once you've got all the schmutz off your CD, you can dry it with a
lint-free cloth. That's so you don't add any more dust or scratches to the
CD surface. Again, rub in a radial direction, from the center out. Now it's
ready to play.
"Stay away from household cleaners. Obviously, abrasive cleaners like Comet
are out, but even harsh chemicals like window and counter cleaners can
sometimes damage the polycarbonate surface on the CD. Stick with mild dish
detergents.
"You could go to the record store and buy a cleaner made especially for CDs,
but there's no evidence they do a better job."
Microsoft will no longer replace your disks for Office 2000 so if this
doesn't work, you might as well be prepared to spend some money.