First i count the number of days between the given dates.

And i sorted the week days according to the Day of the first text box. (then only i can go smooth with the rule)

And divides the total value by 7. It gives how many week days are there,

Then i used division remainder block to count the remaining.

For example, If the Text box1.text day Monday and total count is 7 mean no problem( all the weekdays count will be 1). But If the total value is 10 mean, then from the starting day i have to add one more counting to first three weekdays. i.e Monday-2. Tuesday2, Wed3, thu-1, fri-1, sat-1 and sun-1.(and i achieved this using 7 procedures- more info please see the block)

Because of this reason i am very much concerned with the first day. Also we no need to consider whether the year is leap or not and all. Because everything will come under counting.

So for i didnt find any bug. Experts if find anything please tell me…

Thank you @ajay_kapil , though your idea is simple but it makes me to work a lot… This work may be easy for the experts but i tried of my own.