The FTC issued a press release this month warning consumers that their computers may have been "secretly hijacked" by hackers.

Hackers can install on your computer spam-sending software and spyware. This often occurs when you open malicious e-mail attachments or visit malicious Web sites.

Once achieving control, hackers may track your surfing on the Internet, steal personal information and turn your computer into a spam-sending zombie.

Hijacked computers can become part of the so-called "zombie army" or "botnet." The FTC reports that the botnet includes "tens or hundreds of thousands of home computers sending e-mails by the millions" without the computer owners knowing it.

You can help protect yourself by doing the following:

* Keep updated anti-virus and anti-spyware software on your computer.

* Set your operating system to download and install security patches automatically.

* Be careful opening e-mail attachments or downloading files from received e-mail messages.

* If you download free software, be sure it's from a site you know and trust.

* Use a properly enabled firewall.

* Disconnect from the Internet if you're not using it.

* Check your "sent" email box for messages you did not intend to send.

* Act immediately if your computer is hijacked or infected. Disconnect from the Internet, scan your system using updated anti-virus and anti-spyware software, and report unauthorized access to your ISP. The FBI can be notified of hijacks at www.ic3.gov <<A rel="external" href="http://www.ic3.gov/">http://www.ic3.gov/>; .

More information is available at www.onguardonline.gov <<A rel="external" href="http://www.onguardonline.gov/">http://www.onguardonline.gov/>; .

- Opinions expressed solely are those of the writer. Joseph Pellicciotti is a lawyer, professor and associate vice chancellor at Indiana University Northwest.