First Method of Activation 
 

Download 360 Total Security from here
Install and Run the program. 
Open 360 Total Security and click “Enable Your Premium” in drop-down list
Enter your 25-character key into the field.
Click Register button.


Second Method of Activation 
Manually register on web:

Go to Register .
Enter your 25-character key into the field. 
Click Register button.

If you see key error message when you enter the key, try the following ways to solve it:

Check if you have entered the correct 25 characters. Try to copy or type it again.
If you have multiple 360 accounts, check if you have added this key to another 360 account.
Check if the limit to the amount of license keys has been reached. Refer to “Can I use several keys simultaneously under one account?” .