Because trojans are a very common type of malware that is known to practically all web surfers, it is clear how hard it is to answer the question "how do i remove a trojan virus from my computer?"

A trojan virus makes a PC user think that it is a beneficial Windows application. Thus, trojans often masquerade them as screensavers, packages of video codecs, tray clocks, weather forecast software, messengers, etc. Another major source of trojans is all kinds of illegal programs, cracks and keygens. It is a common practice to include trojans into free antivirus software distributed via peer-to-peer networks (e.g. torrents). This is especially dangerous for end-users because antivirus program cannot detect a trojan before the installation finishes and all updates are downloaded, thus the use of free antivirus software downloaded from suspicious websites or sources imposes a great risk on personal computers.

Moreover, one of the most difficult things in PC maintenance is to remove trojan virus from a PC where software of a suspicious nature has been installed.

BitDefender, a world renowned antivirus software maker, conducted a research based on its statistics. Its purpose was to show which types of threats dominate the Web. The results are shown on the screenshot to the right. -->

It's clearly seen that nine out of ten most encountered threats are trojan viruses.

The first trojan in the list, Trojan.Clicker.CM, displays commercial ads, which "eat" the bandwidth and, as a consequence, slow down the PC.

It should be pretty evident that methods to remove trojan viruses should quickly adapt to the reality, since trojans lead the malware army.

So before learning how to remove trojan virus, it is important to know what this type of malware is in essence.

In short, as the term suggests, a trojan pretends to look and act like it's a legit Windows application. However, its malicious code is programmed to execute operations that no PC owner would like on his computer.

• Trojans are capable of stealing important information (passwords, credit card numbers, etc.) Then the sensitive data is transmitted over the Web to virus creators, who thn are able to take control over infected computers.

• A considerable slow-down in system performance is one of the consequences of trojan virus infection.
• A user may be distracted by unexpected pop-ups with ads (mostly with casino, poker, adult content).
• Trojan viruses attempt to become parts of the infected system by interacting with Windows processes and injecting malicious code into legitimate files executed by the operating system (Winlogon is an example of such injection when a trojan virus is fully loaded after the user enters login details).

Trojans may get involved into distribution of unsolicited emails. Sometimes this type of malware is responsible for attacks on other computers connected to the Internet. While it's a bit scary, in fact any PC infected by a trojan virus may be engaged in decentralized attacks onto servers of government institutions, universities, etc.

A trojan virus uses multiple ways to spread over the Web and replicate itself. That's why if you want to know how to remove the trojan virus, you need to be aware of the ways it infects target computers.

1. Through email attachments. Probably the oldest method of mass distribution, it has grown into a new industry of virus propagation. Modern sophisticated software, dedicated servers, large networks of already infected personal computers are used to send out gazillions of spam emails each and every day. A trojan virus may be attached as a greeting card, wallpaper, animated image, screensaver. Many of them have subjects with "hi, here's a greeting card for you!" words.
2. Once downloaded and executed, a trojan may use the address book to send itself to other computers. That's why it is still worth noting that emails from unknown addresses should never be opened.
3. Trojans widely exploit messaging software, especially popular programs like MSN Messenger/Live Messenger, Yahoo! Messenger, Skype, etc.
4. Trojans may be included into bundles of emoticons for email clients and instant messengers alike.
5. Modern Trojan viruses widely exploit security breeches in Windows Operating system and the popularity of multimedia content available online. For example, zlob trojan, responsible for aggressive distribution of over a hundred of fake antispyware programs, used video codecs to install onto target computers. Whenever a surfer visited a website with embedded malicious code, a window would pop-up asking to install a video codec in order to display a movie. Once the visitor clicked to agree to installation, trojan Zlob infected the system immediately.

Trojans have gained an even worse reputation because of rogue security software which they distribute. Rogue software are bogus programs that pretend to look and act like antivirus or antispyware applications, various system maintenance tools, registry cleaners, etc. They use fake malware scan results and persistent pop-ups trying to scare the user into paying for a "full version" of the program. However, even getting a license key in exchange for some $30 or $100 changes nothing in the way rogue security software behaves. Even annoying pop-ups continue to appear on the desktop at same intervals.

I believe many people became more aware of Web threats thanks to rogue programs, because they got interested in the nature of this phenomenon, which led them to learn something about how to remove a trojan virus.

While it is possible to remove trojan virus manually, the set of steps involved in PC cleaning requires a decent level of computer experience. There's a need to indentify the type of malware, to locate infected or harmful files and registry entries, to download the tools that will help to remove trojan virus.

A common practice implies the use of special software, commonly referred to as 'trojan removers'. It is however important to point out that this type of programs makes a considerable part of antispyware software market, which is a big incentive for some programmers to make quick money by releasing trojan removers with mediocre scanning engines, poor algorithms, and no support.

Therefore I feel it's necessary to warn you, the readers of this hub, that the decision about preferable trojan remover should be done after at least basic research of the available programs. User feedback and reviews are important sources of information, though the quality of reviews of trojan removers often leaves much to be desired.

NOTE: Every program recommended in this hub is 100% safe to use. I give as detailed descriptions as possible, with an accent on vital features not to be found in competitors' software. Same applies to any download links given below.

Some folks prefer to remove trojan virus for free. I myself am a big fan of freeware tools, but there's a big problem here. Some developers of scam software promote their products as free trojan virus removers, to entice web surfers into downloading and installing them. However, such free trojan removers are often more dangerous than trojans. Even scanning of executable files by antivirus programs may show them as clean. This is yet another reason why I advise to make some research before downloading and installing any software that promises to help to remove trojan virus.

Online scanners are an absolutely safe and free way to remove trojan virus. All major antivirus software makers offer online virus scanners on their websites, and these services are available for everybody enjoying a stable Internet connection. Not all of the scanners have same detection rate, and they differ in types of malware they're able to remove.

For trojan viruses involved in the distribution of rogue security programs, there are special tools developed by volunteers. These tools have a very specific targeting and are meant to fight either certain trojans, or a range of malware. Usually such tools are created because major antivirus and antispyware companies fail to address new threats quickly. This happens either due to bugs in scan engines, or requires significant updates.

Command-line anti-malware scaners present another way to remove trojan virus for free. Sadly, I was able to find only two completely free and available scanners: TrendMicro SysClean and a-squared anti-malware command-line scanner. The latter is suitable for PC users with intermediate experience, while TrendMicro software is aimed at advanced users or system administrators.

I'd say this goes without saying; any trojan virus should be removed as quickly as possible.

• you never know what it managed to do in your system, and what it still intends to accomplish.
• a trojan virus rarely is the only guest in the PC system; most of the time its buddies come alond quicker than you wink.

Pretty obvious, right? But many people consider dangerous only those types of malware which distract them from work or mess up PC settings. With trojans, the whole system may work more or less normally for a long time. Trojans are designed to attract as little attention on part of the user as possible.

Whenever I'm asked to name a couple of best programs to remove trojan virus for free, I find myself speechless. It's just impossible to find a best program in the world of security software. Not because there are tons of them (and new products appear montly), but because what is best and what is worst is a subject to debates. I prefer to put it mildly: best trojan remover is only an addition to safe browsing habits and conscientious surfing.

In case with free trojan removers, the situation is changing all the time. About 3 years ago IT pros would name TDS-3 among best of breed programs created to remove trojan viruses. But the program ceased to exist, its support was discontinued. Other products appeared on the scene as promising trojan fighters, but their developers either lost enthusiasm or quit the programming, leaving the software 'half-cooked '.

So in brief, what was well-performing yesterday, might have been left in dust by new products. Some of the old players managed to keep up the pace, too. Therefore my short list of software effective in removing trojan viruses includes only programs that scored awards from trusted reviewers and security labs. I personally tested each program to ensure none of them contains serious bugs.

It is worth noting that popular antivirus software and Internet Security Suites from world-renowned manufacturers show relatively weak trojan virus detection capability. Even identified trojans happen to be too tough for an antivirus to erase them from the system. There are practically no exceptions to this sad fact; no matter what antivirus industry leaders promise to potential customers, their products perform as trojan cleaners with imperfect algorithms.

The 4 programs listed above allow to remove trojan virus for free. Either free editions or fully functional trial versions are available. I do not provide links to DEMO's because those usually provide nothing but the so-called "free scans" (sadly, many no-name antispyware programs are distributed with free-scan option only). What's the point of running a scan without the option to remove the detected trojan virus infections?..

Now you may wonder which software of the 4 recommended would suit you best. I'm not going to use "descriptions from manufacturer" which you can find elsewhere. Instead, I'll share with you my impression about these trojan virus removers.

SuperAntiSpyware is young and very aggressive. The team of programmers behind SAS constantly work to improve the algorithms and implement new features thus providing the protection most competitors only can dream about. In my opinion, SuperAntiSpyware would suit best those owners of home PC's who care a little, if any, about which websites they visit and what files download. This, however, doesn't mean that a decent antivirus protection is of no importance. SuperAntiSpyware only complements antivirus engines, by strengthening the level of protection against many types of malware.

Sunbelt CounterSpy v3 normally scores #1 spot in antispyware tests and ratings. This is a solid security package for business laptops. If business partners look over your shoulder and notice a Sunbelt's icon in system tray, they'll definitely appreciate your choice of security applications. Very robust yet simple in configuration and use, Sunbelt CounterSpy suites business image like a Montblanc pen. (Hint: CounterSpy costs many times less than Montblanc...)

Malwarebyte's anti-malware is a playground for those who like to experiment. Malwarebyte's design allows to stay on the edge of desktop anti-malware programs - fast scans, minimalistic interface, no irrelevant features, new updates delivered several times a day.

a-squared delivers a classic Windows desktop security program. Over a dozen languages supported for instant change of interface. Subprograms to run special tasks. Status window shows information about program components, updated definitions, program upgrades, scan times, last detected threats, prevented malware attacks, and much more.

I'm not telling you that one program performs better than others since such conclusions would be inappropriate. These are current leaders of the security software industry; which one to choose primarily depends on how you want it to look on your desktop.

Goog luck with trojan removal! ;=)

NOTE: Microsoft Windows, EMSI Software, Sunbelt, SUPERAntiSpyware, Malwarebyte's, Bit Defender logos found in this hub are registered trademarks of their respective companies.