backdoor.sybot problem

I am running avast 4 pro and recently ran an online virus scanner on 3 different sites (norton, kasper and another).
They all came up with the fact that I was infected by the trojan backdoor.sybot in the file svshosts.
Avast did not find this or inform me that i was infected. Why not? Is Avast not good enough to find these?
I had to disable system restore and delete the file. Was this the right thing to do?
Advice pls. Also any reasons why avast isnt picking up this trojan. Avast=waste of money?? I hope not

Difficult to say, if you still has that Backdoor, you could send it to Avast and see what they have to say. I think your Avast was up to date?

no. i deleted it. My Avast is totally upto date

Not all AV-Programms are able to find all VIruses. THis can happen even if you use one of the Programms you mentioned in your first post.
What should i say, sh*t happens! :frowning:

how come avast just got an award for finding ALL virus ITW then? this isnt a new virus. if u search svshosts on net u will find it is an old program but still around

An old Virus does not mean that it is ITW. And the names SVSHOST and SVHOST are often used by Malware, so it does not look so obviouse like Malware, because WinXP/2000(?) uses a file called SVCHOST. Also there are many Variants of one Malware.