Session validation problem in Page Load event

Question

hi friend,

Scenario:
          When I login into  Login Page, i creating session of respective user name and redirect into their homepage and i was checking session value in Page Load Event. If session value is there then load or not.
Problems:
1) When i pasted url address of Hom page directly into address bar, its shows Homepage and not redirect into Login Page,
its not checking session value but when i refresh then redirect into login page.
2) and also when i login into page and after logout then i clicked back/forward button on Browser, its showing last accessed pages but i want to be redirect only login page after logout button clicked.

Here my logout code:
                Session.Abandon();
                Response.Redirect("/Login.aspx");

Please Help me, its urgent

Thanks in advance

Regards
Tekk