What to do if your computer is infected with a virus

Virus computer If you have an up-to-date antivirus, when a virus hits your computer and tries to infect it, a pop up appears on the bottom right hand side of the screen warning you about the threat treatment. In most cases it ends like this, but in some scenarios a more powerful and devious virus lurks inside the system, bypassing all the security systems we had set up for protection.

While some viruses and other types of malware are designed simply to wreak havoc on your computer, today’s most popular malware is silentharmless to the overall functioning of the system, but capable of stealing personal data and transmitting it externally to some cybercriminal.

So let’s see in the guide that follows what to do if your computer is hit by a powerful and sneaky viruseliminating all its traces with very powerful and (in most cases) free tools.

READ ALSO -> Best Free Antivirus of 2022 for PC

Maximum attention to anti-virus messages

Whenever we notice the antivirus message where it is written that it comes an infection or malware detected, you must always pay the utmost attention. The best antiviruses remove the virus without asking the user to do anything, simply by giving notice of what has happened. If the warning is the result of a defined user action, such as downloading or installing an infected program, it almost always does the antivirus removes the infected file before it can cause problems.

The same thing happens if the warning appears while visiting a web page. Unfortunately, however, it should be noted that when “a virus is detected“means that the virus did nothing and the computer has been saved. For safety, you can open the antivirus administration window and check the infection report, the name of the virus and where it is written which file has been quarantined or removed.

Currently it is advisable to focus only on antivirus that immediately block the infection, so as to completely prevent access to system files. Among the free ones, the best are certainly Avast and Kasperskyalways at the top of antivirus rankings and able to immediately remove any detected threat.

What to do in case of silent infection

As said several times though the antivirus cannot recognize every infection and it can happen that someone hits the computer even with the most powerful antivirus installed.

In guide on how to know if your computer is infected with virus or malware I explained i main symptoms of when you catch a virus. To make sure everything is okay on your computer however there are some easy ways to ask for a second opinion beyond that of the antivirus.

In fact, if we have any doubts, it is better to use on-demand scan tools, small free programs designed to deeply scan the system and find (for free) any threat that is well hidden from the antivirus scanner. The best free tools you can use right now are:

  • MalwareBytes
  • Hitman Pro
  • AdwCleaner
  • ESET Free Online Scanner
  • Kaspersky Virus Removal Tool

All these tools allow you to perform the thorough system scan without going through the hassle of uninstalling your current antivirus. It is not possible to install more than one antivirus program on a computer.

If one of the scanners reports a problem with a silent virus we advise you to follow a precise procedure to resolveso you can be sure not to leave traces or damage your computer.

1) Eliminate viruses

We start all the tools recommended above one at a time (in on-demand scanning mode), launch the scan and wait for the results; at the end of the cleaning operations we restart the computer e we repeat all the scans to see if the virus is still present in the system.

The antivirus may not be able to remove the infected file if it has replaced a system file or if it behaves like a rootkit, loading at startup and then disappearing from view. Repeat scans is necessary since many malware have the ability to replicate in different areasgo deep and make the antivirus ineffective.

2) Eliminate persistent virus

If the scans still detect the presence of the virus even after the scans it’s worth it start your PC in safe mode can definitely help.

In fact, in safe mode Windows loads only the bare minimum to start, thus leaving all unnecessary processes and services inactive (including the virus). After rebooting in safe mode we launch the scan toolswe wait for the end of the analysis and the elimination of the virus then restart the PC in normal mode.

If everything went well, subsequent scans should come out “clean”, with no new traces of viruses. If we need internet access in safe mode, select Safe Mode with Networking Services in the options menu at startup.

3) PC blocked or unusable

If your computer doesn’t seem usable even in safe mode or if the virus were so ingrained that no antivirus was allowed to start (including scanners downloaded online), our last resort before formatting is i CD Boot Scan O Rescue Disk. These CDs start before Windows, load their operating environment and allow you to scan all the disks on your PC, so as to remove viruses without even starting Windows.

The best Rescue CDs we can use are:

  • Kaspersky Free Rescue Disk
  • Avira Rescue System
  • Trend Micro Rescue Disk
  • Comodo Rescue Disk
  • ESET SysRescue

We burn these scanners into a blank DVD, we insert the disc into the problematic computer player or burner then let’s change the boot order to start the scanning environment. Once the environment is started, we provide access to the Internet and perform the required scan, so as to be able to eliminate all the viruses present on the disks.

In another article we saw how to use the tools of virus scan via USB stickso you can also scan laptops and desktop PCs without a reader and burner.

4) Format and restore

If we are unable to remove a virus or if the system has been irreparably damaged, we can do nothing else restore the operating systemusing one of the many recovery methods that come with Windows 10 and Windows 11.

The recommended procedure in this case is to use the Windows ISO installed on a USB key: in this way we will format the entire disk and avoid the use of images or tools already present on the infected PC. Better to avoid restoring using files and images from a damaged or virus-infected system: we run the risk of getting the active infection back even after recovery.

To proceed then we download the tool Media Creation Tool based on our version of Windows (there is in fact the tool for Windows 10 and Windows 11), we insert the USB key on a healthy PC and use one of the two tools seen a little while ago to create the Windows USB key, as seen in the guide on how install Windows 10 and 11 from USB.

Once the key has been created, insert it into the non-working PC, change the boot order, when requested, press any key to start the system on the key. In the first window that will appear we confirm the language and the initial settings, press on Forward then click on Install.

In the new window we immediately press down on I don’t have a product keywe choose the version of Windows to install, we confirm the user license and, in the next screen, we choose Custom: Install Windows only (advanced option).
Format Windows Now we have to do is select one by one all the partitions present, press on Remove and then press down on Forwardin order to start the actual installation.

Alternatively we can also try to restore Windows with i Windows image file or with the system restorebut they are strongly discouraged: if the virus was already present at the time of the image file creation or configuration restore, it will be present again after the restore is complete.


Windows PC viruses can be very subtle and silent during the infection process, to the point where they escape free antivirus (including good Windows Defender). If the episode is random we can also continue to use a free antivirus (perhaps choosing a different one), but if it happens too often it is better to consider a paid antivirus, which offer a higher level of protection.

If we are undecided about which paid antivirus to try, we can rely on antivirus with free trial, such as those seen in the guide The best paid antivirus for PC with free trial.


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