Revive your PC

Just like cars, home computers need tune-ups.

Unfortunately, most of us have never gotten into the habit. Everybody knows to take their cars for routine service, but we often neglect to perform the common-sense maintenance that can keep our home PCs running well.

That's especially odd when you consider how popular PCs are. In 1997, only about 36 percent of US households had one; today, nearly three-quarters, or 77.6 million American households, do, according to Jupiter Research.

A badly maintained computer doesn't just harm its owner. Now that so many of them are connected to the Internet, they can inflict pain on the rest of us. Lots of Internet spam comes from home computers that have been infected with ''Trojan horse" programs that pump out junk mail. If every user ran a good antivirus program once a week, and had a firewall to detect illicit messages sent from his own PC, we'd be spared billions of these nasty e-mails.

Getting the most from your home system isn't a trivial task. Big companies that spend millions on computer maintenance can't get it right; at home you're on your own. Still, that's no excuse for giving up. Many of the best things you can do are quite easy -- and free. Here's my tune-up checklist:

A virus vaccination
With hundreds of new infections showing up every year, there's no excuse for going online unprotected. The most popular antivirus titles, Symantec's Norton Antivirus and McAfee VirusScan, are comparable in quality and sell for about $50.

But you can't buy antivirus software and then forget about it. Your purchase entitles you to a year's worth of regular Internet updates, to make sure your product catches the latest viruses. You'll have to renew your virus protection every year.

Sponging away spam
There's still no cure for the blight of unwanted e-mail messages. But there are useful techniques for filtering out the worst of it. Some Internet services, including EarthLink, use a system that challenges incoming messages.

If you get a message from someone who has never contacted you before, EarthLink replies with a challenge message that includes an image that can't be read by a computer. Thus, a human being could respond correctly, and his mail goes through. But a spam-spewing computer always flunks the test. Another Internet company, Mailblocks.com, offers a similar service.

Spam-haters can also install filtering software, such as the $40 Norton AntiSpam program, or MailWasher, available free at www.mailwasher.net. These programs ''read" incoming messages and try to decide whether they're spam. Such filters keep getting better, but still pose a risk of discarding legitimate messages by mistake.

Spyware killers
Millions of Internet users have picked up ''spyware" programs that bombard them with unwanted advertisements, while keeping tabs on the users' Web-surfing habits. Fortunately, there are programs that will purge these irksome programs.

Two of the most popular are free. You can download Ad-Aware by visiting www.lavasoftusa.com, or try Spybot-Search and Destroy, at www.safer-networking.org.

Erecting a firewall

If you use an always-connected broadband Internet service, you must use a firewall. These programs shut down many of your computer's data entry and exit ports, thus making the machine invulnerable to some types of attack.

For example, MSBlast, a computer worm that swept around the world last year, entered through open computer ports. MSBlast planted a program that prevented the user's computer from contacting the Microsoft website that distributes repair patches.

Many people think the home networking routers that let you connect multiple computers to a single broadband line are a good substitute for a firewall, and they're partly right. A $50 router will conceal your computers from the network, so attackers can't see them.

But software firewalls are still a good idea, because your computer can still be infected by programs that will try to attack other machines on the Internet. A router probably won't stop such attacks. But a high-quality software firewall will warn you that a program on your own computer is up to no good.

Several software companies sell firewalls, either as part of a security suite or as stand-alone software. One of the best basic firewalls, Zone Alarm, is free for home use. Download it at www.zonelabs.com.

Call for backup
As computer hard drives expand, so does the need to make backup copies of all that data. But most people begrudge the effort needed to copy gigabytes of digital photos and music files. Yet it's easy to save copies, with the right hardware.

About $150 buys an external hard drive from Maxtor or Western Digital that will plug into most PCs and store 800 gigabytes of data in just a few minutes. Or you can use the DVD burner that's becoming standard on new PCs. Each disk will hold over four gigabytes --double that for the new dual-layer DVD burners. That will provide plenty of backup.

Make it automatic
Microsoft Windows has a well-earned reputation for bugginess. Scarcely a week goes by without another flaw being discovered, often a flaw that can be exploited to damage someone's computer. Microsoft has responded by enabling Windows computers to automatically download the latest repair patches over the Internet. This system is especially effective for computer users who keep their machines constantly connected to the Internet.

Every home user should take advantage of these automatic updates, available for users of Windows 98, Me, 2000, and XP. Go to www. microsoft.com/athome, and click the Windows Update link.

Bring on the broadband
How did we ever live without high-speed Internet service at home? It's not just the speed. It's also the ability to keep your computer connected to the Internet around the clock. Instant access to information becomes a utility, like running water or electric lighting.

You could live without broadband, but why? Comcast charges $42.95 a month for its basic service; Verizon has undercut them with a $29.95 DSL broadband package. That's about $6 more expensive than a dial-up account with America Online, but a whole lot faster.

Wonderful WiFi
Millions of homes contain more than one computer, which means they have the makings of a computer network. Machines can now swap files, share the same printer, or even link up for family gaming festivals.

You can accomplish this by running ethernet wires through the walls or along the baseboards. Or you can lay out $50 or so for a WiFi wireless networking router, and another $30 or so per computer for WiFi network cards.

WiFi networking isn't perfect. Performance can be spotty in large houses, and other wireless devices, such as cordless phones, can create signal interference. But in general, WiFi is an excellent home networking solution, and so cheap that no multi-computer household should pass it up.

A safe Web browser
Microsoft's Internet Explorer is the favorite Web browser of computer vandals, who love to exploit its many security holes. Microsoft has issued a series of repair patches to keep customers safe. Maybe it's because Microsoft does a poor job of removing bugs from its software. Or maybe the popularity of Internet Explorer makes it an irresistible target for bad guys.

A growing number of Internet users don't care. They just want a safe browser. And that's why Microsoft's share of the browser market has begun to slide. Thousands are switching to the Mozilla browser, at www. mozilla.org, or Opera, available at www.opera.com. They won't work with many popular browser add-ons, such as the Google toolbar. But they're not as susceptible to the ailments that plague Internet Explorer.

Consider a Macintosh
Apple Computer Inc.'s machines are generally more expensive than rival Windows-based computers. And since they can't run your current Windows software, add the price of substitute Mac software.

That said, nobody makes more elegant computers. Check out the sleek looks of the new iMac. Apple machines come with lots of superb software for audio and video editing and managing digital photos. The Mac's built-in e-mail program has powerful spam filters.

And while it's still a good idea to get antivirus software, few virus writers target the Mac. So while your friends and colleagues are cursing their infected PCs, you're wondering what the fuss is about, and getting on with your work.

Hiawatha Bray can be reached at bray@globe.com.