Log in to the Members Area and look in the "License Keys" section.
If you've lost your password (or never created one), click here and then click Forgot my Password.
If you purchased PerfectIt before May 2018 but have lost your license key, you can retrieve it here. Just enter the email address that you used to buy PerfectIt, and you'll get a mail with your registration details.
If you've lost access to the email address that you purchased, please contact us with as many of the details about your purchase as you can find.