Hi, team,
Ineed your help regarding this issue.
This issue not related SEP,
What happend when you disable/Uninstall NTP feature ?
this issue related for GPO.
Have you checked the firewall. Does it allow RDP connections?
http://social.technet.microsoft.com/Forums/en-US/8d3165c6-5cfb-4c87-a2e1-fcf4e6e453fb/windows-server-2008-r2-remote-assistance-disabled?forum=winserverTS
What's your exact issue here?
Can you please try the same step after uninstall the sep to verify the issue is from SEP side or from other.