More than the limit (Excel XP)

[marj0909]

IF(A3<=30,"NC",IF(AND(C3="SEC",,AND(A3>30,A3<=180)),"SS1",IF(AND(C3="SEC",AND(A3>180,A3<=365)),"SS2",IF(AND(C3<>"SEC",AND(A3>30,A3<=90)),"SU1",IF(AND(C3<>"SEC",AND(A3>90,A3<=120)),"SU2",IF(AND(A3>365,A3<=1825),"Ds",IF(AND(A3>120,A3<=180),"Du",IF(A3>1825,"Ls","Lu"))))))))

Questions and Requirements:
Automatic = will calculate automatically by using the formula
Manual = will input the chosen class, and the amount will calculate automatically.
I am using Excel XP, the formula developed was exactly as it is for the "IF STATEMENT FUNCTIONS", more than the limit will no longer calculate. What are or any alternative functions to be used?
LAST CONDITION: IF(ManualClass="","",FALSE
(I AM LOOKING FOR THIS LAST CRITERIA)

PLEASE HELP ME COMPUTE AND FIND THE LAST CONDITION PERFECTLY OK... THANK YOU.
Marj

[samba_ravi]

SEE THE ATTACHED FILE
Some changes made to your criteria

[marj0909]

Thank you very much!

Hope to ask you again...

(I can't see the star you mentioned nor the "solved" button)