Hi,
There is a known issue, Symantec Endpoint Protection client fails to install to recently updated Windows 8 computers. Please refer to below technote for more details. Check whether you are having the same issue.
http://www.symantec.com/docs/TECH203996
Refer these threads as well:
https://www-secure.symantec.com/connect/forums/121...
https://www-secure.symantec.com/connect/forums/unable-install-sep-my-windows-8-unmanaged-client#comment-8503671