You can identify the email from your McAfee account through the program that is already installed on your computer.
1. Open the McAfee program that was installed on your device;
2. On the Home screen, click My Information menu;
3. On the left side of the screen, your account information will appear, including the e-mail that is registered.
4. With the email displayed, log in to your McAfee account at: http://home.mcafee.com
If you do not see the registration email by the installed program, you will need to contact the manufacturer's support to update the email.