Some of the results produced by search engines can lead to websites that will make a mess of your computer, according to a new study on the Internet's riskiest searches.

Terms like "screensaver," "ringtones," and "free downloads" can produce links to sites that could expose your computer to a wide range of techno-headaches, including pop-up ads and spam. Spyware is another danger sneaky programs that get inside your computer and allow outsiders to observe your online activity.

Ben Edelman, a Ph.D. candidate at Harvard University's economics department, has researched the traps and techno-headaches lurking in some of the websites listed in search engine results.

"The core problem is that there are a bunch of bad guys out there who seek to make money by cluttering up users' computers with junk," he says, "whether it's the whole computer, email inboxes, or by scamming users, getting them to provide credit card numbers."

The search engines themselves aren't dangerous. The danger lies in the websites they list. It's like a lunch buffet where some of the dishes are crawling with salmonella. The food is safe to look at, but how do you know what's safe to eat?

The study, released this month, was sponsored by anti-virus software maker McAfee. It found up to 72 per cent of the websites returned on certain high-risk search engine terms can place you just a click-away from dangerous sites.

"Screensavers" is a common search term that's also a popular trap laid by shady online operators, Edelman says.

Searches for free music downloads are also risky. "Peer-to-peer music sharing, free music, free MP3 download, download music these are all terms where more than a third of the results will infect your computer or send you spam," he says.

Watch out for "ringtones," too.

"Ringtones have a particular scam that's troubling. You give them your phone number to have a ring tone sent to your phone. Buried in the fine print, the first one is free, and then they charge you $5 a month forever. If you search for `ringtones,' 29 per cent of the sites will give you that."

So with all that danger lurking, is it time to cancel your Internet subscription, buy some canned goods and retire to the safety of a bomb shelter?

Exploration is the whole point of the Internet, Edelman says, and that will always require clicking into the unknown. "Be an informed and sophisticated consumer," he says. He uses the example of somebody who wants to get a new screensaver online. "Plan, research, ask for advice, ask an expert if you can find one ... Ask your friend the computer expert what screensaver you should get and where you should get it."

And recognize "the difference between browsing a website and installing a program," Edelman says. Looking at a website is generally safe, but be wary when clicking onto something that will might an intrusive program.

Edelman's research is tied to the promotion of a new application called McAfee SiteAdvisor, which adds an advisory to that list of results your search engine produces. A green checkmark means the site is likely safe, a red X means the site could be trouble.

Bruce Schneier, founder of California-based Counterpane Internet Security and an expert on computer safety issues, says the danger of search engines is already well-established, and the McAfee survey is more about product promotion than real news. "If you write a story saying, my God, it's bad out there, you need this product, then (the security vendor) wins. With security vendors there's lots of fear mongering."

Nonetheless, without having tried SiteAdvisor himself, he says the concept is "not a bad idea."

"It's certainly, in theory, good to block fraudulent sites that load spyware."

Other security vendors are working on the problem, too. An example is ScanSafe, which is currently testing its own early-warning system that can help search engine users avoid those techno-tormentors stalking cyberspace.