Once you know that your machine is infected with a Trojan Horse or virus (or if your machine is exhibiting unexpected behavior and you suspect that something is wrong), then you need to perform certain tasks.
If you know what specific malicious program has infected your computer, you can visit one of several anti-virus web sites and download a removal tool.
Disconnect your computer from the Internet
Depending on what type of Trojan horse or virus you have, intruders may have access to your personal information and may even be using your computer to attack other computers. You can stop this activity by turning off your Internet connection. The best way to accomplish this is to physically disconnect your cable or phone line, but you can also simply “disable” your network connection.
Back up your important files
At this point it is a good idea to take the time to back up your files. If possible, compile all of your photos, documents, Internet favorites, etc., and burn them onto a CD or DVD or save them to some other external storage device. It is vital to note that these files cannot be trusted since they are still potentially infected.
Scan your machine
Since your computer (including its operating system) may be infected with a virus, it is safest to scan the machine from a live CD (or “rescue” CD) rather than a previously installed antivirus program. Many antivirus products provide this functionality. Another alternative is to use a web-based virus removal service, which some antivirus software vendors offer free virus scan.
Reinstall your operating system
If the previous step failed to clean your computer, the most effective option is to wipe or format the hard drive and reinstall the operating system. Although this corrective action will also result in the loss of all your programs and files, it is the only way to ensure your computer is free from backdoors and intruder modifications.
Many computer vendors also offer a rescue partition or disc(s) that will do a factory restore of the system. Check your computer’s user manual to find out whether one of these is provided and how to run it.
Restore your files
If you made a backup your files, now you can now restore your files. Before placing the files back in directories on your computer, you should scan them with your anti-virus software to check them for known viruses.
Protect your computer
To prevent future infections, you should take the following precautions:
If you know what specific malicious program has infected your computer, you can visit one of several anti-virus web sites and download a removal tool.
Disconnect your computer from the Internet
Depending on what type of Trojan horse or virus you have, intruders may have access to your personal information and may even be using your computer to attack other computers. You can stop this activity by turning off your Internet connection. The best way to accomplish this is to physically disconnect your cable or phone line, but you can also simply “disable” your network connection.
Back up your important files
At this point it is a good idea to take the time to back up your files. If possible, compile all of your photos, documents, Internet favorites, etc., and burn them onto a CD or DVD or save them to some other external storage device. It is vital to note that these files cannot be trusted since they are still potentially infected.
Scan your machine
Since your computer (including its operating system) may be infected with a virus, it is safest to scan the machine from a live CD (or “rescue” CD) rather than a previously installed antivirus program. Many antivirus products provide this functionality. Another alternative is to use a web-based virus removal service, which some antivirus software vendors offer free virus scan.
Reinstall your operating system
If the previous step failed to clean your computer, the most effective option is to wipe or format the hard drive and reinstall the operating system. Although this corrective action will also result in the loss of all your programs and files, it is the only way to ensure your computer is free from backdoors and intruder modifications.
Many computer vendors also offer a rescue partition or disc(s) that will do a factory restore of the system. Check your computer’s user manual to find out whether one of these is provided and how to run it.
Restore your files
If you made a backup your files, now you can now restore your files. Before placing the files back in directories on your computer, you should scan them with your anti-virus software to check them for known viruses.
Protect your computer
To prevent future infections, you should take the following precautions:
- Do not open unsolicited attachments in email messages.
- Do not follow unsolicited links.
- Maintain updated anti-virus software.
- Use Internet firewall software.
- Secure your web browser.
- Keep your system patched on daily basis.
