There is no registry twick as per my knowleadge,you can repair your sep client.
See below articles
Window could not start the “Symantec Management Client” Service.
Article:TECH187046|Created: 2012-04-23|Updated: 2012-08-17|Article URL
http://www.symantec.com/docs/TECH187046
You can scan your system for symhelp tool sometime if yous system are infected with virus are not started sep service.
Download the Symantec Help (SymHelp) diagnostic tool to detect Symantec product issues
Article:TECH170752|Created: 2011-09-29|Updated: 2014-06-03|Article URL http://www.symantec.com/docs/TECH170752