How to calculate total work weeks?

Can you explain further the results you are looking for with an example of some detail data and the results you want to see?  It is not clear how you want to summarize this data and its also not clear what you definition is of "weeks work"

For example...
The employee "PATSY SUMROW" worked from 5/10/2010 to 3/10/2014. He worked 5 days a week, and sometimes he worked 3 days a week. He was paid out weekly, so he worked 5 days or not, I paid weekly.
I want to know how many I paid him until certain date.

... and what if they worked in only two weeks out of a 4 week period because they were sick or on vacation.  Do those weeks count?

No. They are all part-time.

I think that the closest I can come is for you to make a Summary report which has an <ask the user> filter on employee and summarizes the time records with a Group by "week". The bottom of the report will have the number of "groups" (weeks).  But I know that does not gigve you a clean employee list for all employees with a clean column with your answer.

Thanks.

I have a situation where I am reporting total projected work weeks scheduled.  There is a start date and an end date where and a formula to calculate the total number of weeks scheduled. 

I am having a problem reporting the information correctly because there can be (1) or more service technicians on site at a time.  I would like to count how many service engineers are assigned to the job and multiply it by the total weeks, then I need to produce a report for how many work weeks are scheduled per month.  Is this possible?  I have a report now but can only calculate the total number of weeks scheduled per work order (it doesn't take into account how many service engineers were on site) and it only shows the total number of weeks in the ending month.  It doesn't show the weeks per month accurately.