I have two formulas that I want to create.

I have data from an assembly equipment tester that has the following columns
A B C D
Date Time Date and Time Difference
6/1/2009 7:00:42 6/1/09 7:00
6/1/2009 7:01:30 6/1/09 7:01 0:00:48
6/1/2009 16:47:52 6/1/09 16:47 0:01:15
6/1/2009 16:48:50 6/1/09 16:48 0:00:58
6/1/2009 16:49:39 6/1/09 16:49 0:00:49
6/2/2009 7:02:01 6/2/09 7:02 14:12:22
6/2/2009 7:03:07 6/2/09 7:03 0:01:06
6/2/2009 7:04:03 6/2/09 7:04 0:00:56
6/2/2009 7:04:54 6/2/09 7:04 0:00:51

The data will continue for an entire month and for about 500 lines a day. I
want to extract the start time and stop time for each day of production to
determine the total production time. (For this Data, it would be 6/1/09 16:48
minus 6/1/09 07:00. I am thinking I need to use a Max, Min & Index function
but I don't know how to combine the just right.

In addition, I want to sum the differences only if they are over a given
time as defined by another cell (in my case it is in B4), but I do not want
to include the time between the end of one day and the start of the following
day.