Conditional Formatting for Excel 2003 - Overdue dates

Hi guys,

I work for the NHS and we use excel 2003 so you have to put in your formatting yourself, something I am not able to do. I desperately need some help with the following:

We receive referrals all year and have to see the patients within 28 days:

Column 1 - Date of Referral
Column 2 - Target Date (28 days)
Column 3 - Assessment Date

I would like my target date to change colour (orange) when it is 7 days before the due date and turn red when it hits the target date and turn white if there is an assessment date within the 28 day target and stay red if the assessment date is over the 28 day target.

Is this possible. How do I complete this task?

Any help would be gratefully received!!!