Virus cleaner = False reassurance ?

[Lars-Erik]

I helped a friend with his x-wifes laptop that was very unstable (Norton AV and all Windows programs closed as soon as they were opened).

So I used the free avast! Virus Cleaner to scan the PC, and it found 6 (six) different viruses (serveral "svchost" viruses).

BUT the virus was still unstable, and I look at the Virus Cleaner "about box" and compared to the Symantec site, and found 3 viruses NOT scanned by the avast! cleaner (Welchia, Anig and Gaobot) and downloaded cleaning utilities for those - and found Welchia and Gaobot too !

Why doesn't the cleaner detect those? Welchia is a very common worm. And for people thinking avast Cleaner detect all common viruses the avast! cleaner gives false reassurance (the system can still be infected).

BTW:  After installing avast! anti virus (home version) and doing a through scan I found even 2 more viruses :-)

[igor]

Well, the people should have never been made to think that avast! Virus Cleaner detects all common viruses - that's why there's a list of detected malware on the avast! Virus Cleaner web page. It doesn't clean Gaobot, it doesn't clean Anig - that's how it is. If a malware isn't listed on the Virus Cleaner page, it's simply not supported.
It should be able to remove Welchia (which is called Nachi here). If you have an undetected "plain" sample (Cleaner doesn't scan archives), you should send it to us, preferably with a note that avast! Virus Cleaner doesn't detect it; we can hardly do anything about it otherwise.