I've seen more customers over the past few weeks with horribly virus-infected computers than I have over the past few months. Maybe the bad guys have released a new wave of "smart" viruses; I don't know. I do know that most PC users have been lulled into a false sense of security by thinking that, because they have an antivirus program installed, they can do anything they want on the Internet.

I also know that the bad guys are smart guys, and they think up new and innovative ways to mess up people's computers every day; by simply installing a "set it and forget it" antivirus program tacked on top of a firewall will not protect you against their nefarious schemes. If you want to enjoy a safe computing experience, you are going to have to change your behavior. If you want to keep your computer off of the repair bench, you may need to stop doing some things that you've been thoughtlessly doing for years.

The main thing that most folks need to stop doing is installing programs and applications that they download from unknown sources on the Internet. Most viruses these days don't come from e-mail attachments; they come from Web sites. Just because someone writes a convincing blurb on some Web site about how great something is does not mean that you should do what they say.

The worst examples of this that I've seen lately are the thousands of innocent-looking Web sites that, as soon as you land on their page, an "alert" starts flashing obnoxiously. This important-looking alert says that a virus has been detected on your computer, and to "click here" to fix the problem. As soon as you "click there," your computer is infected with a nasty piece of virus-like software called WinAntivirus that constantly annoys you with popups. Most antivirus programs have a hard time dealing with this problem.

Some of the fastest-growing areas fraught with danger are social networking Web sites such as MySpace and Facebook. These Frankenstein-like Web sites have grown so rapidly that their owners can no longer effectively protect their users. One scam that was big in September was the "I want my old Facebook back" movement. Facebook programmers, in an effort to improve their Web site, started forcing users towards the "new" Facebook, which featured a completely different look and functionality. This upset a great many Facebook users, who preferred things the way they were before. Scammers exploited this resentment by announcing various ways that users could "get the old Facebook back." Over 700,000 users blindly followed dubious instructions that were posted to numerous Facebook pages, only to find that, instead of getting their old Facebook back, they had been conned into secretly installing an ad-laden entertainment search application. That's one of the more harmless scams that have been run on unwitting Facebook users.

More dangerous is a virus that has been spreading across Facebook in the form of messages that seem to come from legitimate Facebook friends. These messages carry titles such as, "LOL. You've been catched on hidden cam," and "I didn't know you could be so naughty." The messages contain a link to a Web site that looks like a YouTube video player. Those foolish enough to have clicked this far are instructed to download an update in order to view the video. Rather than downloading an update, though, a virus is downloaded into the hapless user's computer.

Be advised that antivirus and antispyware programs are going to have a hard time protecting your computer if you keep opening the door and inviting the bad guys in. Do a little research before you install anything from the Internet, and be suspicious of everything.

Dave Moore has been repairing computers in Norman since 1984, when he borrowed $1,200 to buy a Commodore 64 system. He can be reached at 919-9901 or www.davemoorecomputers.com.