Computers are complicated machines that sometimes make mistakes, for a bug, for a user error, for a sudden hardware problem or even due to the action of a computer virus. When there is a problem with the computer, it can be difficult to get to grips with it and understand the cause. Sometimes unexpected behavior is only random, other times it occurs regularly or in different ways, confusing even more those who have to investigate and repair.
As for PC viruses, just like viruses for humans, the bigger the problems caused, the easier it is to recognize the infection, but if it is less clear and more hidden symptoms, even an expert doctor may have to do several tests before understanding the cause. Viruses on PC, which would be better to call malware, are programs capable of hiding in other files or which load when the computer starts and then disappear, which always have some effect, although often not easy to discover. Below, let's see, then what a virus does on the PC, what are its most visible and least noticeable effects, when it is likely that the computer has been infected with malware and, of course, how to intervene.
READ ALSO: What are the symptoms of viruses and malware for infected Windows PCs
1) Pop-ups of advertisements are opened even when no browser is open or much more advertising appears than usual while browsing the internet, with a continuous automatic opening of sites that are not required. This type of behavior always occurs when adware-type malware has been installed.
2) The browser navigation is redirected to other sites.
Redirecting navigation means that the virus changes browser settings, making sure that if the user wants to open google, something else opens. Sometimes the redirect is more subtle and more dangerous. For example, a banking Trojan could hijack your browser on a fraudulent site that looks identical to the real bank site. In this case, the only indication is the internet address which, even if similar, can never be identical.
3) A new security program opens disturbing warnings .
These messages, coming from security software that we certainly never installed, can warn the user about many problems and viruses on the PC that need to be corrected. Of course, by clicking to correct them, you will be asked to buy that program. In truth all those warnings are false and there is nothing wrong, if not the presence of that malicious software.
4) Our friends on Facebook or in our Email address book receive messages from us that we have never written, usually containing a link to a malicious site. Malware focused on Facebook or other social media sites are propagated by generating fake messages and are the evolution of viruses that propagate via email. Generally these messages speak of sensational things to see absolutely, scandalous photos or incredible videos. By clicking on it, you become a victim of the virus, which can then replicate itself.
5) A program holds the PC hostage and asks to pay a ransom.
This type of malware, called Cryptolocker, is one of the most dangerous today because it can encrypt all the images and documents of the PC asking for money to free them. In other cases, they may display a notice from the Postal Police asking to pay a fine for illegal use of the computer. Of course, even by paying, it won't free your PC from this virus.
6) It becomes impossible to open and use the system tools.
System tools such as the task manager, registry key editor, control panel and user management can be blocked by malware to make it much more difficult for the user to remove it. If trying to use these or other system tools displays an error message or that the administrator has disabled them, it is almost certainly the virus's self-defense.
7) Everything seems perfectly normal.
The most effective and most dangerous malware are those that manage to hide all their activities, without leaving visible traces.
In reality, some trace always remains, only that it is imperceptible. For example, there may be hidden malware waiting for a remote command from its creator to take action, it may be transmitting personal information, or it may be using a small amount of computer power to participate in a hacker's job.
To solve any problem with viruses, to recognize them, find them and remove them, we have quite comprehensive guides in this blog.
In a nutshell, for problems 1 and 2 of the list, we can solve with the ADWCleaner program.
If everything looks normal too, it is important to check every now and then with an antivirus scan.
The most effective free program is definitely Malwarebytes, which in its free version does not offer real time protection, but can be used without limitations for checking.
In absolute I have summarized in other articles all the instructions to remove any malware and to clean your pc from viruses (and prevent other infections in the future) .
