the best way would be to find the uninstall Key from the regisry and use msiexec.exe
check this location
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall
on the right hand side you will find the uninstall string for etrust.
one you find the key save that in a note pad, rename to script.bat run it it should uninstall. for removal of SAV it would look like this
MsiExec.exe /norestart /q/x{C1B0BDC8-0624-4036-90D1-F7DF0EE8C96D} REMOVE=ALL
{C1B0BDC8-0624-4036-90D1-F7DF0EE8C96D} is the uninstall string.
Or else you can use the competative uninstall tool in the CD2 of Symantec Endpoint protection ,
uninstall wrapper,
hope this helps