It seems that NTP is blocking the your network connection , that's the reason you are not able to connect to the internet.
Installed SEP again and go for custom install and select AV and AVS and PTP do not select NTP>
Coming to the Pending chnages requires a reboot is concerned , this is caused bu OS and not Symantec.I feel that there might have been some installation/up-gradation that was done and the system was not restarted so the value is still in the registry.
Rename the value for PendingFilerenameoperation and try the install