Moving the project backward

There should be no reason other than Date Constraints which will prevent you from moving the whole project into the past or into the future just by changing the Start Date in Project, Project Information.
Do you have Date Constraints?

If you simply entered Start and/or Finish dates (a serious "no-no") then those tasks are constrained and will not move. Look to see if there is a little calendar in the Indicators column. If the calendar is there then you’ll have to double-click on the task, select the Advanced tab and change the constraint type to As Soon As Possible.

If you have entered Actuals (by changing the %Complete or by entered actual values for a task) then, again, those tasks are constrained and will not move.

Dear All

I have not entered any percentages this programme has prepared by one of our PM so I don’t know the way he entered the data this is small programme having 15 activities i can send you the progrmme if you can send me the mail address

GA

Not necessary. Just display the Indicators column as you were advised. Alternately, display the "Constraint Type" column -- if it contains anything other than "As Soon As Possible" then you have constraints on the task.

One other remote possibility is that the PM is playing with you (like telling new campers to go on a snipe hunt) and has given you a schedule that has been set up to schedule from the Project Finish date. (Project > Project Information and check the Schedule From date.)

update project in tracking tool