Create Voter Accounts

Hello,

I am in the process of taking over an account that has this poll installed. This is my first exposure to this script. The previous web company somehow installed it such that users can only vote once every 12 hours. I believe this may be based on IP address, but I am not sure. It seems to work decently, but some customers are getting around it. I am being hired to eliminate this problem. My theory is to have visitors create a user account that is activated via an email confirmation. Then only registered users can vote. If they attempt to login to vote within 12 hours of their last vote, I need the script to deny their access. If you have found any other solutions to eliminate undesirable voting, please let me know.