It's called scareware and it's designed to do exactly what it says, scare you into paying for something you don't need and don't want.

According to USA Today, scareware is booming on home computers. Online promotions for scareware increased tenfold in the first quarter of this year, the paper says.

Microsoft reported that its free Malicious Software Removal Tool cleaned scareware off 7.8 million PCs in the last six months of 2009 vs. 5.3 million in the first six months. In the first half of 2009, the AntiPhishing Working Group identified a 583 percent increase in scareware programs.

The most common type of scareware works like this: You visit a website or download a program and suddenly a pop-up window will tell you that your computer is infected with a virus.

It asks you if you want to run a scan and even if you click no, it will tell you that the only way to remove the virus is to download antivirus software for a fee, usually between $30 and $70.

If you bite, what will download is something completely useless or, more likely, harmful. Of course, there never was a virus. And the antivirus program you purchased if you fell for this is a type of malware called rogue security software.

One reason scareware is proliferating is that it is extremely profitable for the bad guys.

Court records from legal proceedings against the Ukraine-based firm Innovative Marketing show exactly how much the company made by selling fake antivirus software: $163,167,539.95 between 2006 and 2008.

Panda Security estimates that such fake security software generates $34 million a month.

Criminals are constantly coming up with inventive ways to infect you. Malware can ride along on a browser plug-in or extension, usually a toolbar. An image, screensaver or archive file attached to an e-mail message, a codec downloaded to play a certain video or software shared on peer-to-peer networks can also be sources of invasions.

Recently, searches for Fourth of July recipes and things having to do with the movie "Twilight" have been hijacked so that high up in the results are malware Web sites. This is a fairly new method called SEO (search engine optimization) poisoning.

How do you deal with scareware? First, don't be scared. If a pop-up on your computer says you are infected, there is a good chance you are not. If you are asked for money to rid you of the infection, that is a solid indication that you are dealing with scareware.

If you see a suspicious virus alert, don't click on anything in it, even a "stop scan" or "cancel" button, says Microsoft spokesman Eric Foster, quoted in USA Today. Clicking on anything usually advances the scam.

If you're using a Windows computer, hit "ctrl-alt-delete" or type "task manager" into the search box to navigate to your Task Manager.

Once you get to your Task Manager, hit the "applications" tab; and find your browser -- Internet Explorer, Firefox, Safari or Chrome -- then force-quit the browser by clicking on it then clicking "end task."

While this will stop any further infection for the moment, you still have to deal with the malware that is on your computer.

Run your security program scan. That may get it. Probably a better idea is to try a program that is specifically anti-malware. Malwarebytes' Anti-Malware is one such program (a free version is available at malwarebytes.org). There are others.

TechMan recently came across rogue software called AV Security Suite. That is just one of hundreds of names, including Antispyware 2010, My Security Wall, Virus Locker and many others, that are basically the same program. The bad guys keep changing aliases.

They often will use a name that is close to the name of a reputable security program. For example, TheSpybot is a rogue program and Spybot - Search and Destroy is reputable.

So never search for free security software on the Web and download it unless you know that it is a reputable program.

You may end up getting a security problem instead of solving one.

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