If you do not want to finish out the trial before installing your purchased license: 

*go to your Documents-->HOMER Energy-->License folder and remove the existing .lic (what is your trial license).
*re-open your HOMER Pro software license; it will send up a screen that reads, "Manage HOMER License".
*click on the blue "License HOMER Pro" button... the software will search/find your purchased license.

Should you continue to experience an issue, please submit a support ticket, so that we may further assist.