You can obtain a free license key from the website, here:http://www.donationcoder.com/Keys/index.php
Then you can enter it via copy (highlight via left click and drag, then Control+C) and paste (Control+V) into the license box that appears when you open the application. If you are not asked for a license when opening the program, go to the Help -> About box and see if there is an option there (it could also be somewhere under the Help menu).
And yes, please do explain your problem more thoroughly. We aren't mind readers