While moving to the second page you'll have to store the value of RadioButton in
Session/cache/cookies
etc. And in page load of the first page check for that. Like:
In page load event of 1st page:
if(Session["Test"] != null)
{
radioButton1.Checked = Convert.ToBoolean(Session["Test"]);
}
While redirecting the page:
Session["Test"] = radioButton1.Checked;
Response.Redirect("Test.aspx");
--Amit