Only supports Windows 8 as Win8 comes with a new feature called secure boot
http://www.howtogeek.com/116569/htg-explains-how-windows-8s-secure-boot-feature-works-what-it-means-for-linux/
Windows 8 Early Launch Anti-Malware (ELAM) support provides a Microsoft-supported way for anti-malware software to start before all other third-party components. In addition, vendors can now control the launching of third-party drivers, depending on trust levels. If a driver is not trusted, it can be removed from the boot sequence. ELAM support makes more efficient rootkit detection possible.
Managing early launch anti-malware (ELAM) detections
http://www.symantec.com/business/support/index?page=content&id=HOWTO81107
Adjusting the Symantec Endpoint Protection early launch anti-malware (ELAM) options
http://www.symantec.com/business/support/index?page=content&id=HOWTO81106
What's new in Symantec Endpoint Protection 12.1.2
http://www.symantec.com/business/support/index?page=content&id=HOWTO81091