Updated 29th Oct'12
Hello Everyone,
We should be familiar with dos commands to start & stop services related to SEP.
Symantec Endpoint Protection Service is dependent on Symantec Web service so when we try to stop web service only it will stop SEPM service also.
Net stop semwebsrv
Type ‘Y’to stop the service, you can see it's stopping SEPM service first then Apache service.
To start both the services again type
Net start semsrv
IF you wish to stop only Symantec Endpoint Protection Manager Service only
Net stop semsrv
To start Symantec Endpoint Protection Manager service again
Net start semsrv
To stop Symantec Endpoint Embedded database service.
net stop sqlanys_sem5
To start it again
net start sqlanys_sem5
How to restart Shared insight cache service through command line if it’s installed.
Sc start “Shared insight cache”
Sc stops “Shared insight cache”
Sc query “Shared insight cache”
In many cases we may required to stop SEP client service to replace sylink.xml or for any other troubleshooting.
To stop SEP client service
smc -stop
After typing this command there won't be any command prompt window, SEP yellow shied icon 
should disappear after typing this command.
To start SEP client service
smc -start
To disable SEP client firewall service
smc -disable –ntp
To enable client firewall service
smc -enable -ntp
If the SEP client UI is password protected:
smc -disable -ntp -p <password>
I hope it's been informative.
Public KB Articles:
Available Command-Line Options for Smc.exe
http://www.symantec.com/docs/TECH103048
Windows commands for the client service
http://www.symantec.com/docs/HOWTO26882
How to uninstall Symantec Endpoint Protection (SEP) client silently using the command line
http://www.symantec.com/docs/TECH105827
MSI command line reference for Symantec Endpoint Protection 11.0
http://www.symantec.com/docs/TECH102668