How can I validate my licence to activate pro version

There are three ways to validate your pro license.

Go to User Meta >> Settings, put your email and password for http://user-meta.com and hit “Validate” button to validate your license.
If first method fails, follow http://user-meta.com/activation/ to remotely validate the license.
If both methods fails, send an email to support(at)user-meta.com with your site url. We will send you validation key.