There's no lack of experts when it comes to computing. Everyone from your brother-in-law to the guy down the street is willing, even eager, to offer advice.

Most of us were introduced to my favorite computing myth when someone helped as we sat down to a computer for the first time.

"Don't worry," the wise expert may have told you. "Nothing you can do will hurt the computer."

The real point of that lesson? Even the teacher can be wrong.

There are thousands of ways that you can kill a computer, and they aren't limited to physical abuse. Fail to update your anti-virus protection and risk losing all your data. Don't use an uninterruptible power supply, or at least a surge protector, and your computer can go up in a puff of smoke.

One widespread myth is that — compared to any other operating system — Windows has more holes than all the nation's golf courses together. You are told that Linux, Unix or Macintosh using an operating system based on Linux are all bulletproof, while Windows is a time bomb.

I won't argue that Windows is perfectly secure. But a study by the federal government found that in 2005, "out of 5,198 reported vulnerabilities, 812 were Windows operating system vulnerabilities, while 2,328 were Unix/Linux operating vulnerabilities and 2,058 were multiple operating system vulnerabilities."

Another myth involves cookies, the high-tech variety. Most of my readers think that they are pure poison for a computer.

A computer cookie is a small text file. It's often used — in a good and harmless way — to make things easier for you when you log on to a Web site. For instance, if you set a "start" page at the Weather Channel site (www.weather.com) with the weather for your town, a cookie is created on your computer's hard disk. That cookie is used — each time you log on to the Weather Channel site — to create your personalized page.

Cookies aren't viruses or spyware. They aren't even programs. They are just text files.

Can they be harmful? Sure. But the "bad" cookies are usually found on hacker or X-rated sites. Just as is true in real life, if you stay in safe neighborhoods while cruising the Web, you'll usually be fine.

Just as they think that cookies are bad, many people think that surge protectors offer an ironclad defense against lightning strikes.

That's not so. If a bolt of lightning hits the power line going into your home, there's a good chance that it'll turn your computer into a crispy critter. That lightning bolt jumped across a big hunk of sky before it hit your power line, and it can sure jump an inch or less inside your surge protector.

Folks, if those things were lightning protectors, that's what it would say on the box. Instead, surge protectors attempt to shield your computer from surges in electrical current. A lightning strike isn't a surge, it's a danged tsunami.

Finally, we come to screen savers. At one time, they had an important mission. Old black-and-white computer monitors often suffered from a problem called "burn in." If you left something on the screen long enough, the image burned into the screen's phosphorus coating.

An LCD screen doesn't suffer from that problem at all, and modern color cathode ray tube monitors are reasonably immune.

So screen savers are good for blocking the screen from prying eyes or just for amusement — but do nothing to save a screen.

That's it for computers and myths. I'll leave you with one bit of lore that's absolutely true: Your computer is most likely to fail at a time when you need it most.

— Bill Husted writes for the Atlanta Journal-Constitution. E-mail: bhusted@ajc.com.