As Perth's top computer repair shop, we deal with a LOT of virus infected computers.
A high percentage of our client's run a good assortmentment of internet security products. From Norton all the way to free ones.
Some even run two or three internet security products simultaneously in the mistaken belief that this strategy will improve their protection.
It is an urban myth that Internet Security products can give you a 100% cast iron guarantee against virus infections. This is because anti virus solutions are always reactionary.
By the time a new virus strain has been identified, a patch or defence developed against it, the patch issued as an update and then all the client machines collect the update (if they can) then the new virus strain has had time to party!!!
Do not underestimate the amount of very clever software and social engineering that goes into making and distributing a virus.
Most viruses are tested against the market leaders of anti-virus solutions BEFORE they are released into the wild. This makes sure the the virus can have the maximum impact
If you have the misfortune to get a virus infection, then the first thing the virus will do is disable your anti-virus software.
Most of the time, your anti-virus solutions is totally unaware that is has been 'doctored' and reports that all is well while in reality the infection is running amok and most likely bring down other infections in the background to from what is known as a 'nested virus infection'.
So if your computer is crashing, running slow or behaving oddly, then there is a high probability that you laptop or computer has been infected despite your AV solution saying all is well.
At this point, because your anti-virus solution has been ham-strung, the best solution is to take the infected computer to a local virus removal expert and get them to remove it