Trojans are viruses that masquerade as legitimate programs and then wreak havoc once they're installed. In this eHow article, you will learn how to remove them.
Step1
The first thing you must do is install anti-virus and anti-spyware software, which are available at computer stores and online websites. There are paid and free versions of both anti-virus software (like Norton and AVG) and anti-spyware software (like McAfee Security Suite and Spybot Search and Destroy). The free software often works as well as the paid software, so keep that in mind. Step2
Once the software is installed, make sure that it's updated. Because each software is different, it's outside the scope of this article to describe exactly how to update the software, but most security software has rather prominent "Update" buttons integrated with the main interface.Note: some Trojans will prevent security software from running. If this is the case, plug a high-capacity USB drive into a separate clean computer and install the software onto the USB drive.
Step3
Once the software has been installed and updated, start the scans by clicking the relevant "Scan" buttons in the software. Wait until the scans are completed; if you interrupt them, they may not completely delete the virus. Furthermore, make sure to scan external USB drives and flash drives, as these can carry viruses between computers. Step4
Once the trojan is gone, you must prevent re-infection by following good habits. Don't open e-mail attachments from unknown persons and don't install unknown files. 
