If you’ve purchased the Pro version of Driver Easy, you can follow this activation guide to activate the Pro version of Driver Easy. Here’s how to do it:
1) Run Driver Easy.
2) Click UPGRADE to Driver Easy Pro.

3) Enter your license key (use the license key in the email you’ve received after you placed your order), then click the Activate button.

4) Click OK.

Now you’ve successfully activated Driver Easy Pro! Enjoy!

You can refer to the post FAQ on License Key Issues for more information about Driver Easy license key.