hello friends

i am now working with a project.my login page and rest of pages are working correctly.
my logout page looks like this:

<%@LANGUAGE="VBSCRIPT" CODEPAGE="1252"%>
<%
Response.Buffer=True
session.Abandon()
response.Clear()
Response.Redirect("../admin/index.asp")
%>

when i logout it logs out. but when i click back button of browser ,it will take you to previous page.however the links will not work, but i can view the page.
could anybody please tell me how to block this .

ihave also added Response.Expires=-1000 in all the pages

thank you
waiting for any response