Virus question

Stop me if I am being dim, but I thought that the whole idea of AVG. Windows Defender, Spybot etc. was tp prevent the computer being infected by KNOWN viruses? Obviously new ones are going to get through. So how come on my usual Virus sweep AVG picked up a Virus which has been around under different names for a long time? If it was a new version then AVG should not have been able to remove it, as it did with no apparent trouble.
Confusion reigns supreme.

 

I not quite sure that I totally understand the problem, Palustris.

As I understand it, not every virus is caught in the act of entering your computer, which is why you need a regular sweep of your hard disk. This should pick up any viruses that you have picked up since the last sweep. The virus may be old, but it may not have been on your machine for long.

Also every day or two AVG downloads new virus definitions, so that a virus that may have been on your machine for a while, won't be picked up until your machine has the definitions that will allow it to be detected, as Woo said.

Another complication is that a virus can come down in one form, but once it is on your machine it can change its form. This is one method of trying to avoid detection..

 

Still confused as this was an old old virus from mid 90's in the name which AVG found it.
I still thought that Virus programs were designed to 'catch' incoming virus, so this old one should not have got on to my machine in the first place if the program was doing its job.
For example Windows Essentials warned me that something was trying to download the other day and stopped it.

 

I think I understand your query now Palustris. I believe the whole field of viruses and malware is very large and complicated. It would be nice to think that an anti-virus program would catch all viruses at the point of entry. But I don't think that's true.

Of the ones that they can detect, they don't neccessarily catch them all at entry, which is why you need to have regular sweeps in addition. There is also a lot of stuff that they don't detect. They are probably pretty good at the really nasty virus end, but there is a lot of other malware that may not appear to damage your computer, but which spy on you, reporting your actions to their base URL, or create advertising pop-ups, etc, or redirect you to sites that you don't want to go to. It could be that they have reclassified an old piece of malware and only just added it to their dictionary.

There are a lot of good free anti-virus tools on the internet. In the past I have used a number of them such as Ad-Aware, Spy Bot etc. They can pick up different things from you main anti-virus. If you have got half a life-time to spare you can learn a lot from Googling things like "anti spyware tools", which inturn lead to other associated topics.

 

Am I alone in thinking the virus thing is a bit overdone.
It certainly creates a lot of money for the ones that are reputed to be foiling them.

I dont doubt they are out there, but after spending pounds on Mac affee, and then being told it was ****, after it let a virus through, I'm very skeptical about the whole set up.

I'm getting from time to time very strange messages from AVG, telling me I have this and that on my PC.
If thats the case why didn't it stop it????

On the one occasion that I did pick up a virus, Mac affee was no use what so ever, and my PC was cleaned for me professionally.

 

Could it be that although that particular virus has been around for a long time, it had only recently infected your computer?