Online Polls

Suppose I wanted to make a poll of who you think will win the next presidental election, how would I go about that?

I can make the buttons but I cant get the results to show and make it so you cant vote again.

You'll never make it so I can't vote again.  That's why online polls/petitions mean < 0.  As for the rest.. you'll have to have a form with your buttons and a submit.  After submission, tally the results and post them to the user.  You'll need a database to store your results.  To at least try and prevent a user from re-submitting, store a cookie on their system with some value, check for the cookie upon submission and if it exists, don't let the submission continue.