Why not use conditional formatting?

Use a format of:
=a1a2
and color it, say, red

The cells which don't match will be highlighted in red

Regards,
Fred

"Mallymoo" wrote in message
...
I would like to have a box pop-up to alert me when two numbers in my
spreadsheet do not match. Can somebody please let me know how this is
done?

If that is not possible, I would like to insert a box control that when it
is clicked and the numbers do not match, it will colour them to alert me.

Cheers