Suzanne,
Try using conditional formatting.
Select the cell in question.
Go to format, conditional formatting.
Under the "condition" pick "forumla is".
Now, assume that the cell you're concerned about is C9.
Type =(C9=FALSE) into that box.
Then, click on format and pick the "color" box and select white.
This should do it.
One thing to watch out for. If it doesn't work, go back in and look at the formula you typed. If Excell put quotes around any part of it, remove the quotes, hit OK and try again.
Art