Pop up login help!

Hi im here again ... again and again hehe

for login pop up ...
the login pop up will appear at the first you visit the page...
but when you choose the "do not display again" it will never be back to pop once u visit the site again
My question is how can i pop it again instead of deleting cookies?
because not all the user who will visit on my site knows about deleting cookies
most of user is just browsing you know...what im talking about

There is no other option i am afraid.