I'm in the process of checking through a few computers that I help friends by looking after remotely. I started with 4 last night (inc. my own, I have 12 to look after). Each PC has an Anti-Virus program installed and it runs all the time.

So far I have found 2 nasties with Malwarebytes Anti-Malware.

This is good compared to when I first installed the software on their computers.

They have a mixed level of expertise on the computer side of things and a wide range of what they do on their computers.

Each knows to give me a shout if they accidentally pick something up or notice something untoward. However things continue to slip though the net.

Avast, like many other AV programs, will pick up a great deal of nasties and block many of them. However there are still plenty which will get past it. This is why IMHO it is important to use a strategy which utilises multiple methods.