A study performed by AOL (apparently) proofs once again that the average computer user is unfamiliar with the security terminology. Many people don't really know what a trojan is, or what spyware means. Some quotes:

A quarter said they knew what "spyware" was, although almost one in 10 of those thought it was a computer program that kept an eye on unfaithful partners.

A surprising 16% had never heard of the term "spam" to describe unsolicited e-mail, even though 76% were worried about junk e-mails.

What works in these conditions are the "set it and forget it" techniques to periodically scan and secure your computer. An antivirus/anti-spyware program should do its own scanning/updating every night automatically. Windows Update in XP SP2 should also automatically install the latest service pack and eventually reboot the machine.