I'm not quite sure I understand; but you could try this formula in P4:
=IF(L4>TODAY();"Still valid";"Quote Expired")

Hopefully it will get you started.

Per Erik

Assuming you have dates in O2 and L4, in cell P4 use this formula:

=IF(O2<L4,"Still Valid","Quote Expired")

Then just set the conditional formatting for cells A4 to P4 to a
formula:
Green formula:
=P4="Still Valid"

Red formula
=P4="Quote Expired"

Hope that helps!
Cory

You don't say what happens when L2 is equal to today, so I assume that it is
still valid.

You need two things.

First you need a formula in P4 of

=IF(O2<=L2),"Still valid","Quote expired")

Then you and conditional formatting

-select P4
- goto CF, format>Conditional Formatting
- change the 2nd dropdown to 'equal to'
- enter Still valid in the textbox
- click the format button
- select the Patterns tab
- choose a shade of green
- click OK
- click the Add >> button
- change the 2nd dropdown to 'equal to'
- enter Expired in the textbox
- click the format button
- select the Patterns tab
- choose a shade of red
- click OK
- click OK

You are done.