I got a virus which could not be detected by Avast! 4.7 home. It deleted my Avast!, Sunbelt Kerio firewall, Ad-Aware and Spybot executables as soon as it detects it. When I reinstall the antivirus and run on boot, it does not find a virus and once logged in the virus deletes the antivirus executable again. Also when I am connected to the Internet it starts sending some data (not sure what though). I cannot do a system restore back to any days before the virus was infected. I have looked at the startup programs in registry and don’t see anything unusual. Any ideas on what the virus is and how to resolve it?
There is a similar topic http://forum.avast.com/index.php?topic=25822.0
Use this tool to scan your PC - http://www.f-secure.com/blacklight/ Wink
You probably still have an infection, probably a rootkit on your system that is killing avast.
See http://forum.avast.com/index.php?topic=26554.0
http://forum.avast.com/index.php?topic=25941.0
http://research.pandasoftware.com/blogs/research/archive/2006/12/14/Rootkit-cleaner.aspx
http://www.f-secure.com/blacklight/try_blacklight.html
After running the above rootkit tools if nothing is found try these.
If you haven’t already got this software (freeware), download, install, update and run it, preferably in safe mode.
AVG anti-spyware or SUPERantispyware or Spyware Terminator.