This site is designed to take advantage of CSS. If you are seeing this, CSS must not be available or enabled in your browser. Everything should still work, but won't be as pretty. :)
Open the Licenses window in the application. If it has a Licensed Email field, simply enter your name and the email address you used when you purchased, then click Find, and the serial number will be looked up for you. Otherwise, you can email us and we'll be happy to manually find it for you. It would help us if you can tell us approximately when you bought the software (e.g. "late 1998"), but all we need is your name.