Activate protection. Turn on your operating system's firewall, spam blocker or other built-in security application if available. Activate spam filtering and other online protection provided by an Internet Service Provider or e-mail service.

Shut down an idle computer. Turning off the computer when not used for long periods, or at least disconnecting the Internet cable, can reduce the chance that a malicious remote computer will access it.

Use public computers with care. Don't conduct financial or other personal business on computers at libraries, hotels or airports. The same goes when using a personal computer on a public wireless network.

Consider Mac. Although Mac computer owners face the same problems with spam and phishing as Windows users, they have far less to fear from viruses and spyware. Because Macs are less prevalent, online criminals get less of a return on their investment when targeting them.

Beware downloads. The myriad free utilities, games and other software on the Internet can be useful, but many are laden with viruses and spyware. Stick to downloads from well-known manufacturers or trusted sites.

Be cautious with e-mail. If you get an e-mail or pop-up message asking for sensitive personal information -- such as account numbers, passwords, Social Security number or birth date -- don't reply or click the link. In any case, never send personal information via e-mail because it's not secure.

For more tips and information on who to contact if something goes wrong online, visit www.consumerreports.org to access Consumer Reports' "State of the Net" report, or the Federal Trade Commission's Internet fraud site, www.onguardonline.gov.