Anti Antivirus = ? Virus ?? Trojan ??

Recently i visited a site Iptools.com and downloaded some files from there and started to scan with trojan remover and Nortan AV 2003 (On Xp no Sp1) After Scanning two zip filoes I suddenly noticed that Scan with NAV option was greyed out. I saw that tray Icon also dissapeared and NAV was dead (.

So I did a online scan fom symantec(no virus detected) Uninstalled and reinstalled NAV.
But this did not help. Both Navapw32 and navapsvc are loaded as seen in task manager but NAV does not open and scan is not possible. I got the message :
Error: "A settings violation has been detected. The security settings have been tampered with." (1004,1)
"Settings alert! Some Symantec product settings have been changed by an unauthorized program. This can indicate that an attacker or a virus is attempting" to disable your program. To avoid problems settings will be reverted to their previous configuration and the system will be restarted."
Restart obvoiusly did not help.
I did Uninstall NAV and run the Rnav2003.exe removal utility for NAV 2003 also. Removed all keys I thought were relared to NAV/Symantec. Then I repaired Internet explorer thinking it could be a possible culprit.
Reinstall NAV 2003 = same problem.
Then I installed NAV 2002. Now during the last parts of the setup "Norton AntiVirus Information Wizard" I get Internet explorer Script error
url = res://C:\Program Files\Norton AntiVirus\Cfgwiz.exe/CfgWizRoadmap.htm
Script error : Permission denied.
and the next button for registration, setup live update and AUTOPROTECT are all disabled.(the page CfgWizRoadmap.htm comes from Cfgwiz.exe Hence I replaced it with a fresh copy from the setup). I have also tried decreasing Internet security options to minimum. Also script blocking is already disabled in NAV. Still I am getting this "Permission denied" Script error is preventing me enabling Autoprotect.

I uninstalled NAV 2003 and Installed Dr. Web(AV) but this also doesnot run - hangs the system with 100% CPU usage and dispaly starts corruption.
No viruses R detected by another copy of NAV 2003 in Second Partion - win98(but XP - NTFS partion was not scanned).
I am frustated with it and thinking Clean Install of XP is the only option .
Anybody has encountered a similar problem ? Could it be new virus/trojan?
How can I correct the script error ?
Please Help