Symantic anti-virus client removal when there is a password required is accomplished as in this article.
1. Open Registry Editor (regedit).
2. Navigate to the following registry key:
HKEY_LOCAL_MACHINE\SOFTWARE\INTEL\LANDesk\VirusPro tect6\CurrentVersion\Administrator Only\Security\
3. Change the value for useVPuninstallpassword key from 1 to 0.
4. Exit Registry Editor and now you can uninstall Symantec AntiVirus Client.