To authorize online, first install Live. Get the most up-to-date installer for your version at
www.ableton.com/account/downloadsWhen starting Live, you will see an authorization dialog:
1. Click "Authorize with ableton.com"
2. Your web browser will open and take you to ableton.com, where you will be prompted to log in to your Ableton user account (or create a user account if you don't have one yet)
3. Once you're logged in, your Ableton license(s) are displayed in a list. (If you don't see your license, click on "Add a new product" and enter your serial number)
4. Click the "Authorize" button next to your license
5. The ableton.com server will send authorization information to your computer and launch Live if it is not already open. Live will then automatically authorize