Slow down, restart or shut down your computer.

Copy fake links to false websites, display porno sites, play sounds/videos, display images.

Log keystrokes to steal information such as passwords and credit card numbers.

Gather e-mail addresses and use them for spam.

Upload and download files without your knowledge.

Allow remote access to your computer (by a remote access trojan).

Deactivate or interfere with anti-virus and firewall programs.

Help to spread other malware such as viruses (by a dropper trojan).

Erase, overwrite or corrupt data on a computer.

Some typical examples of threats by trojans are as follows:

On the surface, trojans appear benign and harmless, but once the infected code is run, trojans kick in and perform malicious functions to harm the computer system without the users' knowledge.įor example, waterfalls.scr is a waterfall screen saver as originally claimed by the author, but it can be associated with malware and become a trojan to unload hidden programs and allow unauthorized access to the users' PC.

Unlike viruses or worms, trojans do not replicate themselves, but they can be just as destructive. It is possible that you could be forced to reformat your USB flash drive or other portable device in order to eliminate the infection and avoid transferring it to other machines. You may also inadvertently transfer malware via a USB flash drive or other portable media. Like spyware and adware, trojans can get onto your computer in a number of ways, including: from a web browser via email or in a bundle with other software downloaded from the Internet. Bitdefender Antivirus Free is a set and forget piece of software that is bloatware free and therefore, lightweight.Ībout Trojans and Multiple Anti-malware Programs Trojans, Malware and Threats.zip file contains both the 32-bit and 64-bit versions.) However, there is a FreeFixer user forum to help you with the scan results and the software is regularly updated.A FreeFixer Portable version is available here.

Extra care must be taken as deletion of crucial files could damage your system.

FreeFixer scans your system and can remove trojans and other malware but the user has to be able to interpret the results.

As they are not rated in this review, I am listing them here with brief descriptions and links to their sites for ease of reference: These are a number of other free trojan scanners and removers which were brought up in comments here or noted from other sources. Might cause CPU issues on certain systems.

Free trojan horse remover