Hi John,
use Conditional Formatting which you should find in the Format menu.
Use this eg as a guide...
Say the range of cell to be formatted so that more than 38 characters
results in a red fill happens to be A1:D10, then...

1. Select A1:D10 then go FormatConditional Formatting
2. Under the blue heading "Condition 1" is a box with "Cell Value Is".
Click on that box's down arrow then select ""Formula Is".
3. Click in the next box to the right and type the following formula...

=LEN(A1)38

4. Click on the Format... button to see the Format Cells dialog
5. Click on the Patterns tab of that dialog then select red then OK
6. Click OK on the conditional Formatting dialog.

Hope this makes sense.

Ken Johnson