How about a drop down list in each cell with "Yes" and "No" as the choices?
If so, here's how:
1. On another sheet (you could hide the sheet after if you want) put Yes
and No in two cells (e.g. A1 and A2).
2. Back on your input sheet, highlight the range you want to have the drop
down lists.
3. From the DATA menu, choose VALIDATION.
4. Choose LIST.
5. In SOURCE you can click on the button to the right and go highlight you
choices (the Yes and No on the other sheet).
6. You can then get fancy and add an input and error message.
Once you click OK your cells will have a drop down button on the right and
your user's won't be able to choose anything other than the list you selected.
Hope this helps.
Bob Tulk
MOUS