Newbie to this group...

We keep all of our company info on a complicated but nicely formatted little
excell spread sheet.  Is there anyway to prevent/protect the formatted cells
from someone deleting/typing in them?

In other words, if cell C3 is the sum of cell C1 and C2, how can I prevent
anyone from changing C3, but allow them to enter info in cells C1 and C2?
Needless to say, losing the formatting defeats the whole purpose and I have
spent hours going through the spread sheet trying to find where the
formatting was deleted/changed.

I am using 2000 on one computer and 98 on another.

Thanks!