Unable to reload Norton AntiVirus - valid digital signature not found

[jgw1998]

After the nightmare to remove a bunch adware (TV Media, eZula, PowerScan.... over 20+ items), I was unable to start Norton Antivirus 2003 in my Dell Windows XP Prof system. (Norton AntiVirus has encountered an internal program error. 3002.1530).

So I uninstall and tried to re-install this Norton AntiVirus 2003 or Norton Systemwork. At the end of the installation I get this message:

Symantac CCApp "A valid digital signature was not found for this component. <NAVProd>" (1002,2)

Following Norton AntiVirus knowledgebase instructions, I done:
1. uninstall the Norton Antivirus
2. boot to safe mode and run FixKlex.com. Found no W32.Klex.E worm
3. turn off system restore
4. run regsvr32 wintrust.dll. DllRegisterServerSucceeded.
5. Make sure that the Windows Cryptographic service is running
6. download and install the Microsoft Windows Script 5.6 for Windows 2000 and XP

According to:

http://service1.symantec.com/SUPPORT/sharedtech.nsf/7e7f15291a25d938882567e5

0048a048/757d01ad3ba02c8488256dcd005fd38f?OpenDocument&src=bar_sch_nam

Reinstall Norton AntiVirus 2003 again & again, same error message, same problem, unable to run after installation.

Any advise and help is much appreciated.