I searched Google, found malware

I knew I might be in trouble as soon as it happened.

I had just clicked on an innocuous link in a Google search at work and came upon one of those random pages of links. You know the ones; they're totally unrelated to whatever the search results showed.

I backed out and clicked on the next link but was redirected back to the first page.

Uh-oh.

I tried one more link - same result - and quickly closed the browser. When I opened a new browser, to my relief, everything seemed to be in order.

I forgot about it until the next day when I arrived at work and woke up my computer. Waiting for me was a pop-up warning me that my computer had been infected and directing me to download certain software to fix it. Readers write in with this scenario every month, and unfortunately far too many people click to download the software, a mistake that only makes matters worse by opening the user to more malware.

I knew better, so I hustled over to our IT guy's office and asked for help. To make a long story short, it turned out I had downloaded spyware so stubborn that the IT staff had to reinstall Windows on my machine to remove it.

The spyware's purpose, the IT guy said, seemed to be to generate higher click-through rates for certain sites. Other than being annoying, it wasn't particularly harmful.

According to security software company AVG, 95 percent of online threats are Web-based and can't be stopped with antivirus software alone. Online criminals set up their own Web sites or poison existing ones, and one in eight Web users will come across a poisoned page at least once a month, the company reports. Visitors to these sites can fall victim to "drive-by downloads," or malware that downloads to their computers without their knowledge.

To protect surfers from these threats, AVG came up with LinkScanner, a free program that detects dangerous pages before you click on them. McAfee SiteAdvisor, also free, does the same thing. You can find them at linkscanner.avg.com and www.siteadvisor.com.

McAfee's software gets its information from a network of test computers that run comprehensive security tests on Web sites every day. They look for everything from dangerous downloads to fishye-mail practices and give each link a rating in search results.

AVG's product checks each page in real time before it opens on your PC. It places a safety rating next to each search result and stops you from opening poisoned sites.

Both are simple downloads, but if you're trying to install them in Firefox, you may have to go to the add-ons menu (under "Tools") to activate the application.

I installed both on my computer and found them pretty much equal. A couple of sites received mixed reviews;McAfee hadn't tested them yet, but AVG's on-the-spot scan rated them safe.

Either way, you've got a pretty safe bet. My husband chose McAfee for his laptop and our desktop; I picked AVG for my work computer but will probably leave both on my computer at home - you can never be too careful.