authentication error in log out

Hi All,

I wes using login view an login status to achieve authentication in my app.

But after logging out if I press the back button of the browser, it is still going back to Home page.

What may be the error.

Here is the code.

protected void Login1_Authenticate(object sender, AuthenticateEventArgs e)
{
if ((Login1.UserName == "sana") && (Login1.Password == "sana"))
{
FormsAuthentication.RedirectFromLoginPage(Login1.UserName, false);
}
else
{
e.Authenticated = false;
}

}

I have used this line to sign out..

FormsAuthentication.SignOut();