Count number of dates between two date ranges, with two criteria

Hi
I am trying to do a summary sheet on a workbook that counts the number of jobs running on each week (not just those that start during a particular week). I have tried using Countifs, and Sumproduct but cannot get this right so need some help please. Working on Excel 2007.

Attachment is a sample workbook with the summary on Sheet 2 (Summary)- the numbers indicated in Yellow cells are those I want to see, but I need to put in a formula in each cell so it will be auto-populated by the data being entered into Sheet 1 (Data).
The two criteria are the Project Name (Col A) and the Project Manager (Col B). I need to know how many projects each manager has running during each week.

Pivot tables may be one way to do this but not really what I want to do with this.

Thanks
Steve