Hi,

       Please refer the following link and let us know whether it helped.

http://service1.symantec.com/SUPPORT/ent-security.nsf/docid/2002031914291648

Norton removal Utility can be downloaded from here
http://service1.symantec.com/Support/tsgeninfo.nsf...

Manually delete these folders

C:\Program Files\Symantec or C:\Program Files\SAV or C:\Program Files\Norton
C:Program Files\Common Files\Symantec
C:\Documents and Settings\All Users\Application Data\Symantec

Note C: is your root drive so it might be diffrent
After removing these try installing SEP 11.0 or SAV 10.1

Have you try removing manually the ap0.edb file?

use  Cleanswipe and delete all folders created by symantec . also try msi Cleaner .you can download from
http://support.microsoft.com/kb/290301

I'm not sure if it would work but you could try Revo uninstaller, it a free software.

I forgot to mention one more thing it will work only above version 8 or 9 i am not sure but it will not work on 7.5
thanks...

Ask for the clean wipe version 3.3 and not the latest version(4.X) IF USING SAV.

You can use NoNav to uninstall previous version of symantec/norton antivirus.

Norton removal tool will not remove Corporate or Enterprise Editions. Also Cleanwipe needs to be used with proper guidance as incorrect usage it may result in loss of network connectivity. I am not sure about NoNav either.

Better way is to perform a manual uninstall.

> Stop the Symantec services ( Start > Run > Services.msc)
> Download the Windows Installer CleanUp utility from
   http://support.microsoft.com/default.aspx?scid=kb;en-us;290301
> Look for any entry which says Norton, Symantec, ccApp, ccCommon, SPBBC, LiveUpdate, etc and remove them.
> Restart the computer.
> Backup the registry & then remove Symantec related folders, if they are still present.
  e.g., HKEY_LOCAL_MACHINE\Software\Symantec
           HKEY_CLASSES_ROOT\Software\Symantec
          
> Then try to delete the Symantec folders in the C: drive if they are present (drive where you have the old Norton/Symantec programs were installed)
   e.g.,  C:\Program Files\Symantec
            C:\Program Files\Common Files\Symantec Shared
            C:\Documents and Settings\All Users\Application Data\Symantec  (Application Data folder will be hidden)

> If you have difficulty in removing folders, try in safe mode.
> Restart the computer & then try installing Symantec Endpoint Protection.
> This has worked in most of the cases.

Regards,
Mac