How I keep my computer secure

It's Saturday morning. The kids have had breakfast and are planted in front of the TV. I'm off to do my weekly computer security check.

Making sure that my machine is safe is a weekly routine. It's something anyone using the Internet needs to be prepared to do. A recent white paper on Internet security found that once you connect a computer to the Internet, you can expect it to be attacked in about 60 seconds.

What, or who, is doing the attacking? Viruses may lurk in e-mail attachments. Trojan horses try to install themselves on your hard drive when you visit a website. Adware and spyware sneak onto your machine when you download certain kinds of software. Hackers attempt to turn your machine into a "zombie" that sends out spam without your knowledge.

I'm always on the lookout for the unusual: Perhaps my machine is running slowly, or it suddenly reboots itself. Maybe there's less hard-drive space than there was yesterday, or maybe my machine seems to be doing things on the Internet without me being online.

First, I run updates for the security software on my two desktop machines. I have Symantec software on one, MacAfee on the other. This past week, MacAfee told me about the W32/IRCbot.worm, which can cause my machine to continuously reboot. As long as my security software is up to date, I'm protected.

Unfortunately, even security software can make mistakes. MacAfee has owned up to the fact that its products were misidentifying some legitimate programs as malicious - and deleting or quarantining them.

Updating is key. Many programs can be set to automatically update your antivirus protection, but it doesn't hurt to manually download new updates and patches just to be sure.

Get patches and security updates for Windows operating systems and programs (Internet Explorer, Outlook) at the Windows site. Mac users can go to the Apple Macintosh site for the same thing.

About 200,000 known viruses can attack a machine operating with Windows, but only 200 can affect a Mac. So people with security concerns, straightforward computing needs, and the ability to pay more might consider a Mac.

After downloading patches and updates onto my computer, I run my security software and fix any problems it finds. It can take a while to run a scan. You can set your computer to run the program at night.

I don't have any file-sharing software (Grokster, etc.), but if you do, it's worth making sure your file-sharing is properly set. Any program that lets you share music, photos, or files online can also allow access to other folders on your computer.

When you install a file-sharing program and it asks you what folder you want to share, do not hit the "Next" button. This could permit access to all folders. Instead, designate a specific folder for material you will share. If you already downloaded a file-sharing program, double-check: Go to each folder in "My documents" and right-click on the folder. Select "Sharing and Security," and block access to the folder.

Next, I run my adware- and spyware-detection software. Spyware tracks your movement on the Internet without your knowing it. You may download them by just visiting a website. While they don't hurt your machine in most cases, they can slow your computer to a crawl.

How bad can it be? I downloaded LavaSoft's free Ad-Aware SE Personal spyware protection for a friend recently and ran it on his machine. It detected (and removed) 200-plus foreign "objects."

LavaSoft is free, but you can purchase additional protection. PestPatrol is also good. For a comprehensive list of programs, visit SpywareGuide.com.

Some of my security precautions occur daily. I never open an e-mail from someone I don't know if it contains an attachment. I'm even wary of messages that seem to come from those I do know. This morning, for instance, just before writing this column, I noticed an e-mail from someone with the subject line "Thanks for dinner."

Dinner? I haven't had dinner out in months. Someone, I suspected, was trying to sneak something onto my machine. I deleted it, unopened.

Trust your instincts. If something seems strange or unusual, it probably is.