I need to find the earliest login time and latest logout time by day by user
so that I can work out how long they worked on that day. I have a record of
each login and each logout of the system but can't get my sumproduct to work
("Stolen" from an earlier post in 2007).

The data runs from columns A - D.

The formula I'm trying to use is:

=SUMPRODUCT(--($B$1:$B$35=MIN($B$1:$B$35)),--($D$1:$D$35=$I2),--($A$2:$A$35=J$1))

I2 contains UserA and J1:O1 contains dates

The data is as below

Date Login Logout User
17-Sep 13:05:25 15:45:07 User A
17-Sep 16:27:51 16:35:46 User A
17-Sep 16:37:45 20:02:23 User A
19-Sep 12:04:38 12:24:53 User A
19-Sep 12:25:00 14:20:40 User A
19-Sep 14:22:19 14:41:44 User A
19-Sep 15:20:22 17:00:54 User A
19-Sep 17:07:28 18:00:23 User A
20-Sep 16:06:45 19:59:40 User A