I haven't done formulas in a while but can someone help me out with the following.  I attached a screen shot below.  

If %Complete is 100% then status would be blue

If end date  is less than 10 days away then status would be yellow

If end date is on or past end date then status would be red.





Try this one.

=IF([% Complete]@row = 1, "Blue", IF(AND([End Date]@row < TODAY(10), [End Date]@row > TODAY()), "Yellow", IF([End Date]@row <= TODAY(), "Red", "Green")))

Let me kow if you have any questions.