Access registry on client machine
Take reg back up
Sometimes its hard to uninstall SEP client if uninstall password is lost or SEPM is down.
In such cases you may follow these steps
Start - Run
type smc -stop ( If it prompts for password; navigate to HKEY_LOCAL_MACHINE\SOFTWARE\Symantec\Symantec Endpoint Protection\SMC, delete the smcexit key and then type smc -stop)
Navigate to HKEY_LOCAL_MACHINE\SOFTWARE\Symantec\Symantec Endpoint Protection\SMC
look for smcinstdata key; delete it
go to add/remove program and uninstall the client..