Recovering from a Trojan Horse or Virus

Recovering from a Trojan Horse or Virus 



It can happen to anyone. Considering the vast number of viruses and Trojan horses traversing
the Internet at any given moment, it’s amazing it doesn’t happen to everyone. Hindsight may
dictate that you could have done a better job of protecting yourself, but that does little to help
you out of your current predicament. 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), what can you do?
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. Chances are, however, that you will
not be able to identify the specific program. Unfortunately your other choices are limited, but
the following steps may help save your computer and your files.
1. Call IT support 

If you have an IT support department at your disposal, notify them immediately and follow
their instructions.

2. 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.

3. 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. (Actually, it’s good practice to back up your files on a regular
basis so that if they do get infected, you might have an uninfected set you can restore.)

4. Scan your machine 

Since your computer (including its operating system) may be infected with a malicious program,
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 (try
searching on “online virus scan”).
The next best action is to install an antivirus program from an uncontaminated source such as a
CD-ROM. If you don’t have one, there are many to choose from, but all of them should provide
the tools you need.