Hi,
The liveupdate and tamper protection options can be disabled from the primary server using Symantec System Center (SSC). So there is a possibility that it is the same reason why you are seeing this disabled.
You can try with uninstall from add or remove programs. If it was configured with uninstall password you will get a prompt while yo click on uninstall.
If it asks for a password then
Open Registry Editor (regedit).
Navigate to the following registry key:
HKEY_LOCAL_MACHINE\SOFTWARE\INTEL\LANDesk\VirusProtect6\CurrentVersion\Administrator Only\Security\
Change the value for useVPuninstallpassword key from 1 to 0.
Exit Registry Editor and now you can uninstall Symantec AntiVirus Client.
Hope this helps!