Who said that for delete trojans from PC need to buy expensive cybersecurity software suites? In fact, there are many free resources that perfectly fulfill this task e, in terms of effectiveness, have absolutely nothing to envy to paid solutions: here are some examples.
The first line of defense against Trojans is represented by theantivirus, so be sure to use one that is proven effective and keep it constantly updated. There are several that can do for you, even free of charge. However, if you use a PC equipped with Windows 10, I highly recommend you to use Windows Defender, the antivirus included "steard" in the Microsoft operating system which, in the last comparative tests, has performed very well e, given its integration into Windows, does not slow down the PC.
To make sure Windows Defender is up and running on your PC, search Windows security in Cortana's search bar (the one located at the bottom left of the screen) and click on the first occurrence found, in order to open the management panel of the Windows security components.
In the window that is proposed to you later, select the item Virus and threat protection from the left sidebar and analyze what is reported on the screen: if you are asked to take actions to increase the security of your PC, run them.
Going into more detail, to activate the protection against trojans and other threats, you have to click on the item Manage settings related to the section Virus and threat protection settings e, if necessary, move on On the levers relating to the options Real-time protection, Cloud-Provided Protection, Automatic submission of sample files and Tamper protection (optional).
Once this is done, to update the antivirus definitions and make sure that they are updated automatically from the PC, go back to the screen Virus and threat protection settings and click on your voice Check the updates present nella sezione Virus and threat protection updates. Then click on the button Check for updates, to check for updates.
To verify, instead, the activation of automatic updates, you must contact Windows Update: the system that takes care of downloading and installing operating system updates. Then click on the button Home (the flag icon located in the lower left corner of the screen) and press onicona dell'ingranaggio on the side, in the menu that opens, to access the settings of the PC.
With that done, go up Update and security, select the voice Windows Update from the left sidebar e, if necessary, activate the automatic update of Windows and its components (including Windows Defender), by pressing on the appropriate item. For more details, you can read my guide on how to update Windows 10.
Are you using an older version of Windows and / or does Windows Defender not meet your tastes? In this case, I invite you to try Bitdefender Free: a free antivirus that in the last comparative tests has stood out for its effectiveness and for its heuristic system, i.e. for the technology used by the program to detect threats not yet included in the antivirus signatures (an operation that is carried out by analyzing the behavior of processes running on the computer).
To download Bitdefender Free on your computer, connect to the program's website and click on the button Download it for free. Once the download is complete, open the file .exe obtained and follow the instructions on the screen to complete the setup, start a first system scan and register a free account, necessary to use the program at no cost.
Bitdefender Free isn't the only valid free antivirus - there are at least two or three others that I recommend you consider. Find out which ones by reading my post on the best free antivirus
Use supporting antimalware
In an area like cybersecurity it is essential to have a "second opinion" you can rely on. That's why I recommend pairing your antivirus with a antimalware software not to be kept constantly active on the system but to be used "on-deme", from time to time, to be sure that the antivirus has not left out anything important during its scans.
The free version of Malwarebytes Anti-Malware, in this sense, it is one of the best solutions that can be adopted: it is an excellent antimalware software capable of delete trojan, spyware, worms, rootkits and other types of cyber threats without checking the system in real time (this function is reserved for the paid version of the program, which costs 39,99 euros / year).
To download Malwarebytes Anti-Malware on your PC, connect to its official website and press the button first Free download and then Download now. A download complete, apri il file .exe obtained and first click on Yes and then OK, Computer for personal use, Continue, Accept and install and end, but will conclude the setup.
At this point, start Malwarebytes Anti-Malware e, in the window that opens, close the message relating to the 14-day trial to test the paid version of the software (it is the one that includes the system control module in real time, which I advise you to deactivate: you can do it by moving the relative levers in the right sidebar).
Successively select the voice Scan from the left sidebar, select the tile Search for harmful elements and click on the button Start Scan, to start a system check. The operation could go on for several minutes, it all depends on the power of the PC in use and the amount of data to be analyzed.
After the scan is complete, if any potential threats have been found on your computer, click the for button first remove them and then Close, to eliminate them (or rather, put them in quarantine to ensure that they can no longer cause damage to the system). You may be required to restart your PC to apply the changes.
If any of the steps are not clear to you and / or you want more information on Malwarebytes Anti-Malware, read the guide I have dedicated to the program.
In the most serious cases, when neither the antivirus installed on the PC nor the support antimalware are able to eradicate the Trojans present in the system, it is necessary to rely on a self-starting antivirus. What is it about? An antivirus that, once copied onto a USB stick or floppy disk, can be started outside the computer's operating system and used to fight threats such as viruses, worms, trojans and so on.
There are several self-starting antiviruses worth considering: one of them is definitely Kaspersky Rescue Disk, which is completely free and very simple to use.
To download it to your PC, connect to its official website and click on the button Download. You will thus obtain aISO image to copy onto a USB pendrive or to burn to a CD / DVD, using any burning software (I have recommended several in my guide on how to burn ISO).
Once you have created the USB key or disk containing Kaspersky Rescue, insert the media into the computer to be "cleaned" and restart the system. When the message appears on the screen Press any key to enter the menu, press any key on your computer keyboard and the antivirus should start automatically. If this does not happen, read my guide on how to enter the PC BIOS and set the USB port or CD / DVD drive as the primary boot drive on the computer (instead of the hard disk).
At this point, select the language English from the initial Kaspersky menu then select the item Kaspersky Rescue Disk. Graphic Mode, to load the Kaspersky Rescue desktop.
Once the Kaspersky workspace is loaded, accept the condizioni d'uso of the software, by checking the relevant boxes and pressing the appropriate button; then you need to connect to the internet (to receive definition updates). Provide, then, to connect the computer to the router via Ethernet cable or click on the icon due monitorini, bottom right, to connect to a wireless network.
Once the connection is established, click on the button Start Scan present in the Kaspersky Rescue Tool (which should have opened automatically) and wait for the system scan to run. If any threats are found, agree to delete them.
Despite having put into practice all the tips I've given you so far, haven't you been able to get your PC back on track? Well, I'm sorry. I have to admit it's weird; maybe there is some hardware problem that you have not thought about and that could prevent your computer from working properly (eg RAM or disk problems). In any case, as they say, don't beage your head yet before you break it!
Before contacting a technician to repair your computer, try formating your PC and reinstalling the operating system on it. I would also recommend a preventive backup of your data, but in this way you would risk saving and copying on the new system any malware that gave rise to the (bad) situation your computer is in now.
Despite what some might believe, i Mac they are not "invincible": they are not immune to viruses or Trojans. The number of threats designed for Apple's home system is infinitely less than that of threats designed for Windows, this is true (especially since Windows, being installed on about 90% of computers around the world, is a greedy prey and profitable for the bad guys), but don't let your guard down.
If you are using a Mac it might be a good idea to install a antimalware per macOS and use it, from time to time, to scan your system. Unless you do particularly "reckless" activities with the computer, there is no need to keep it running constantly like on Windows, but a scan from time to time is highly recommended.
In this regard, I recommend that you use Malwarebytes Anti-Malware which, even in its Mac version, is confirmed as one of the best free computer protection solutions (even on macOS, real-time protection, which in any case does not advice, it is agolable as a paid feature).
In addition to occasionally checking the system with Malwarebytes Anti-Malware, make sure you install all the updates agolable for macOS and do not download software from untrustworthy sources