session state

Question

Hello.
 I am using the session object and also using the membership in my project.
whenever some one login in the site , their information like gender , userid  saved in the session also the authenticated user credntial like their userinfo stored in the membership which we get using httpcontext.

 My question is that whenver someone login  in the site and after some time they clear their private data from browser like cookies then all the information abt session  expire. and where i use session in the site it now show the error.
 is there any way to check and  redirect automatically to default page when this session not avaliable.
 i donot want to check session on page load events of all the pages.

pls help......