Hi webber and craigb. Thanks you for your reply and suggestions. I did have another AV installed on that troubled WinXP machine: Symantec Antivirus 10.1.5.500. It is notorious for not being able to be uninstalled using Control Panel → Add/Remove Programs even after disabling ALL Symantec services (9 of them) and stopping running Symantec processes. It is a real software “dinosaur” that I will never use again.

There is a manual procedure on uninstalling SAV 10.1 for those who is interested and have 2hrs of spare time to do it:
http://www.symantec.com/business/support/index?page=content&id=TECH101706&locale=en_US

I have tried to use Nonav.exe program to clean up SAV from the system downloaded from the link suggested by craigb
http://singularlabs.com/uninstallers/security-software/

It partially worked uninstalling some of it but still leaving other SAV remnants behind, e.g. MS Outlook plugin, a few SAV services, Live Update etc.

However, the main problem has been fixed: the three avast! Shields: File System, P2P and IM started “magically” running. I did not have to do anything to avast!

What is left to do is more cleaning of SAV from my system including registry cleaning. Bye bye Symantec, hello Avast!

Thanks for you help guys.

Tech_art :slight_smile: