I have a major formula that I'm trying to figure out and I needed some help.

Column A= ID#s
Column B= Status
Column C= End dates
Column D=Responses

Column D responses are as follows:
AL 7/8/08
NI 8/9/08
WL 6/20/08
RCC 7/8/08
WLC 5/15/08
Each cell in a column can have only one of these responses.

I basically want to do the following:

For all ID#'s (Column A):
If status (column B) = "Closed"
AND If first 2 letters of (column D) = "AL"
Extract date out.
Find out the # of network days between extracted date and end date (column C)
and count them if the # of network days <=5

Repeat for all ID#s

I know I will be using sumproduct, but how do I extract dates, convert them
to date format, find the networdays? Can I use sumproduct with networkdays??