How to Get Rid of a Trojan That Keeps Coming Back

By Jeff Orloff

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Trojan horse programs are malware that allow a remote attacker to access an infected computer. Trojan horses are often loaded onto a computer by an unsuspecting user who installs the malware under the premise that he's installing a legitimate file or visiting a legitimate website. Removing most Trojans is a matter of running the right security software; however, sometimes these files remain to reinfect a computer.

Step 1

Turn off Windows System Restore. In Windows XP, right-click on "My Computer," and select "Properties." Click on the "System Restore" tab, and place a check mark in the box next to "Turn off System Restore on all drives." Click on "OK." In Windows Vista, right-click on the "Computer" icon, and choose "Properties." Click on the "System Protection" link. A window opens with the list of disks on your computer. Remove the check marks next to the drives, and click on the “Turn System Restore Off” button.

Step 2

Update your antivirus software's virus definitions, and then scan your computer. Run a "Full Scan" as opposed to a "Quick Scan." Scan every available drive connected to your computer, including external storage drives, flash drives and backup drives. Scan all of your backup files, as well. Remove or quarantine any malware.

Step 3

Download Malwarebytes Anti Malware. When the download's complete, open the software, and click on "OK" to update the definitions. Once the update is complete, run a "Full Scan." This can take up to an hour, depending on your computer. Click on "Show Results," and then "Remove Selected" to clean out any infections.

Step 4

Download and install a firewall on your computer. ZoneAlarm is a free firewall that many people use. This notifies you when someone is trying to access your computer. It also stops outgoing connections from your computer to the attacker's.

Step 5

Refrain from backing up any executable (.exe), screensaver (.scr), autorun (.ini) or script (.PHP, .ASP and .HTML) files in the future. These files may be hiding Trojan horse files.