Hello,
Check this article:
How to uninstall Symantec Antivirus, Symantec Endpoint Protection,and Symantec Endpoint Protection Manager, and what to do if that fails
http://www.symantec.com/business/support/index?page=content&id=TECH104790
You can also try uninstalling SEP via Cleanwipe Utility, for which you would have to call the Support and create a case.