I'd check your autocorrect options.

Tools -> Autocorrect options
See if you have something there that would change C to a blank for some
reason.

"Stacey" <Stacey@discussions.microsoft.com> wrote in message
news:D544625F-DC6D-4614-85E7-C3653334F900@microsoft.com...
> We use Excel 2002. It's been working beautifully. Today, when we type
> the
> letter "c" as the only entry in a cell, it disappears after we go to the
> next
> cell. Any suggestions?
>
> Thanks a bunch.