You can download the whole thing from Adobe.com. This web site tells you how to do it. Follow the instructions TO THE LETTER.
Click the red logo at the top of this page, then click the My Adobe link near the upper-right. Find the My order history and My products link, and log in as needed with your user ID. Do you find your serial number there?
If you don't find your serial number there, and you do not have your own copy of the serial number squirreled-away somewhere, you're kind of SOL. Your serial number is your proof of ownership of the license.