How do I see which devices I have protected?

Thank you for renewing the Maximum Security! Since Maximum Security renewal will auto update your existing installation to use the new serial number and continue to protect the activated devices after license renewal, you don't have to do anything at all. : -)  You will received an notification email asking you to upgrade your program to the latest version.

To check the devices which are being protected by Maximum Security, you can refer to below steps to log into you Trend Micro Account:

1. Open the Trend Micro Account (My Account) website
2. Type your Trend Micro Account email address and password, and then click Sign In.
3. Look for your product from the product list.

Please let us know if you have more questions! Thank you.

Trend Micro Home Users Community

But what about the two other computers that have changed their email addresses. They wont get any messages

Thank you for asking! If you could not receive the notification email on the other computers, we suggest that you refer to the following support page to verify and to upgrade your program to the latest version on the other computers.
Checking if you are running the latest version of Trend Micro Security software

Please let me know if this answer meets your needs. Thank you.

Trend Micro Home Users Community