One way:

Say your data runs in columns A:Z. Select from A4 to the end of your
data (so say, A4:Z1000), with A4 the active cell.

Choose Format/Conditional Formatting, and set the dropdown and input box
to read

Formula is =COUNTIF($A1:$Z3,A4)=0

Click Format and choose red from the Patterns pane.





In article . com,
Dickery wrote:

Hello
I have a spreadsheet with many rows and cols of numbers.
1 2 3 4 5 5 6 6 7 7 8 8 67 5 4 4 3 4 3 545 6 6 7 7
7 8 8 67 5 4 4 3 4 3 545 6 6 7 7 3 3 3 4 5 6 4 3
......

I want to do a mark the cells red if the specific value does not exist
in the previous 3 rows. Can this be done. If so pl give some ways of
doing it.

Thanks

Seede