HI,
What error do you have received ?
You can remove for Add/remove program..
Or
If you don't have any uninstall password change registry setting.
HKEY_LOCAL_MACHINE\SOFTWARE\Symantec\Symantec Endpoint Protection\AV\AdministratorOnly\Security\UseVPUninstallPassword
Set to 0 to disable
Or
you can use cleanwipe. you need to contact technical support to avail this tool.
How to manually uninstall Symantec Endpoint Protection client from Windows Vista, Windows 7, and Windows 2008 32-bit
http://www.symantec.com/docs/TECH102286
How to manually uninstall Symantec Endpoint Protection client from Windows 2000/ XP/2003
http://www.symantec.com/docs/TECH102261
How to uninstall Symantec Endpoint Protection client from Windows XP and Windows 2003 32-bit and 64-bit operating systems manually
http://www.symantec.com/docs/TECH163585
How to manually uninstall Symantec Endpoint Protection Manager 12.1 on all Windows operating systems
http://www.symantec.com/docs/TECH163684
Manual uninstallation documents for Symantec Endpoint Protection