$session = CGI::Session->new(undef, $sid, {Directory=>'C:/apache/sessions',NoCreateIfNotExists=>1});

##</code><code>##

my $sid = $foo->cookie('main') || undef;
my $session; # = undef
if (defined $sid) {
  $session = CGI::Session->new(undef, $sid, {Directory => 'c:/apache/sessions'});
  $session->delete() if $session->is_new();
}