right formula to include it in conditional format when I need to include many criterias

Hi

Higilight your cell-range. Let's say A2. Then in CF rules uses these formulaw(eatch one for eatch condition).

Formula:

=LEFT(A2,2)="S1"

Formula:

=LEFT(A2,2)="S2"

How can you use Conditional Formating.

--In Excel 2007 and 2010, Conditional Formatting is in the Styles group on the Home tab. In Excel 2003, Conditional Formatting is on the Format menu. See here how you can work using CF.