I installed Norton Internet Security 21.0 on new ASUS Windows 8.1 laptop, but could not activate. We removed McAfee first using add and remove. Then installed from a disc. NIS 21.0 would not activate using a remaining activation key. Also, couldn't sign into Symantec. So, we logged into Symantec through Internet Explorer and downloaded from my account. The download went smoothly, however the activation screen never completed, and could not activate again. Any ideas why NIS won't activate?