reloading page on click of a back button

Question

I am facing a very peculiar problem as follows. I am opening a pop up whenever user clicks on specific control in my datalist. now there are different controls in my datalist. Onclicking of some controls the page is redirected to another page and onlicking on some controls i am opening a pop up. now if I click on a control which redirectes me to other page and press back button then it again opens up a pop up window which it should not.. i.e. on pressing back button how can i disable that action of opening of pop up.? is there any way to do this?whenever back button is pressed my page is should be completely reloaded as it loads initially. please help.. amol