Is it just me, or is my 5-year-old home computer starting to tick off each second louder than the last as its clock works its way toward a New Year's Day calamity?

Unlike the 500-MHz monster that arrived a few months ago all factory-prepped for the next millennium, that old faithful PC, now demoted to homework and game duties, is my Y2K accident waiting to happen. Its future as anything more than an over-qualified paperweight seems assured, unless someone defuses its built-in technological time bomb. Someone meaning me.

According to Y2K computer experts, I'm not alone. The scariest estimates expect more than 70 percent of home PCs to fail completely or falter somehow once they are booted up in the next century. More conservative PC prophets call those predictions alarmist bunk, but offer no better clue to just how many home computers will go haywire when their calendar mechanisms mistakenly read the two-digit year "00" as 1900 instead of 2000. What most experts do agree on is that with only 67 days left before we skid head-on into Y2K's malfunction junction, many home PC users are confused about what they must do to make sure their computers survive the 68th day.

"I think there's a large proportion of them out there that really haven't addressed it," says Dave Cunningham, program manager for Dell Computer's Year 2000 Worldwide program. "I say that because of the types of questions I get when they ask, 'Is my PC compliant?' "

By now, home PC users probably know the so-called "millennium bug" could infect their computers, Cunningham says, but many don't know how, or what to do about it. Yet, of all the foreseeable things that can go wrong come 2000, the home PC puzzle is one that ordinary non-techies can solve themselves. "They have full capability to affect the outcome for their own PC and their data," he says. "But they really need to check their computer."

Don't check and fix your older computer's Y2K flaws and the consequences can range from tainted data to total crash. Y2K computer expert Mike Wendland, whose new 20-page booklet "Y2K: Help For Your Home PC" is available free from Zip drive-maker Iomega Corp. (call 888-233-8566), warns that owners of noncompliant computers could see "disappearing e-mails and computer files" and "wrong dates on your electronic checkbook register." Not coincidentally, Iomega's Y2K sage advises that even before testing for Y2K readiness, back up all important data.

Cunningham reports that in testing older systems for Y2K outcomes, Dell and other manufacturers found some crashed and irreparably corrupted hard drives in rare cases. More typically, "computers simply aren't going to boot up," he forecasts. "But that's probably the least of the problems. If that occurs, you are kind of safe because it hasn't messed up any of your data."

Worst case scenario? "The date has not rolled over, but the system boots up and runs fine anyway," he explains. "Your financial spreadsheets or something like that are using an incorrect date for calculations and you have no idea it's doing this."

But which computers are at risk? The rule of thumb is that if your home computer is older than two years, there's a good chance it's not compliant with industry standards for making a trouble-free Y2K transition (Macintosh computers are not affected). Older than three years and you should bet on it not celebrating on New Year's Day.

But the only certain way of knowing is to contact the manufacturer for its compliance statement on your specific computer. So determine your computer's brand, model and processor speed, and then go to your manufacturer's Y2K Web page. Most are providing Y2K fixes for their systems that aren't up to snuff--usually a free software utility "patch," or a BIOS (Basic Input/Output System) upgrade, or both.

Dell's polished Year 2000 Web pages (http://www.dell.com/year2000), for instance, include comprehensive compliance statements for all of its models, software products and accessories--plus what to do when they aren't compliant. It links to the National Standards Testing Laboratories' (NSTL) "YMARK2000," a free program that when downloaded tests the BIOS and real-time clock (RTC)--hardware's usual suspects in Y2K mishaps.

Dell also provides a free BIOS upgrade, a free software fix for a computer whose BIOS can't be upgraded, and a free test of 17 "extended dates" after Jan. 1, when more glitches could occur. At Gateway's more subdued Year 2000 Web site (http://www.gateway.com/about/y2k), you can find step-by-step details on how to manually reset your computer's clock after the new year, which may be the only hardware fix your model requires. Though don't count on it: Computer testing has found that the manual reset doesn't hold on some models.

My chop shop-built computer is what the industry calls "a white box," one that defies manufacturer identification. So I went directly to the best catch-all Y2K site online. The PC Y2000 Alliance (http://www.pcy2000.org) was created in May by nine of the world's leading manufacturers and technology suppliers, from Acer to Symantec, to assist in solving Y2K computer problems. "It doesn't matter whose PC you've got, what the Web site does is give you step-by-step information on what you should do" to check your hardware's compliance, says Dell's Cunningham.

At PCY2000.org, I downloaded the NSTL's YMARK2000 hardware test. It took about two minutes to analyze my computer. The verdict wasn't good: Of five or so critical measures it tested, my Pandora's box passed only one--it read leap years correctly through 2009. As for "real-time" progression into the new year, and its ability to retain a manual reset, it flunked big-time.

But since Y2K testing online doesn't cost a cent, I sought a second opinion. IBM's foolproof PC Year 2000 Evaluation Tool, downloadable free from its Web site (http://www.pc.ibm.com /year2000), promised to provide a heads-up in five problematic areas. Bad news again: In as much time as it takes to say "Oh, oh," this test reported four critical Y2K problems, same as the NSTL test. It even tried to update the BIOS century byte, the real-time clock, and something called the post-century byte, and couldn't.

In search of a cheap cure, I visited several more Y2K test sites, including PC Magazine's (http://www.zdnet.com/pcmag/special/y2k), which offers a wealth of guidance and another free compliance test. But I also discovered a dizzying number of sites that offer free Y2K testing, but charge for the fixes. "Beware of those who offer you a free test but want to sell you a solution," Cunningham says. "In many cases, the test will lead you to believe that you have a problem when you really don't.

"I can take some of these tests and flunk a brand new computer on them. There are some vendors who are trying to make a quick buck off of this stuff. They're playing on confusion and fear."

Cunningham also is wary of the flood of commercial Y2K software tests and remedies on computer store shelves. "The software utility for $29.95--the thing is, you don't need all that stuff," he says, recommending that consumers stick with commercial programs from reputable companies such as Norton and MacAfee, which will be around long after the new year passes.

I installed one of the recommended commercial products to compare it with the free tests. Greenwich Mean Time's "Check 2000 PC 3.1," an $18.95 program, promised to run seven date BIOS checks, a BIOS fix, an operating system date setting check, an application file scan, and test date dependency information. Within minutes, it confirmed basically the same problems as the other tests and instructed me in fixing my Windows date setting. It also found that while several after-the-fact date roll-overs passed the test, the most critical one on New Year's Day came up as the year 1900. It recommended I upgrade my BIOS.

Convinced that BIOS tinkering was beyond me, I tried one more test-and-fix program. The $29 IntelliFIX 2000's box stated it would fix my BIOS problem, the real-time clock, and bugs in my operating system and software. When the main hardware features again failed the Y2K test miserably, this program offered the option of installing a memory-resident "fix" that in effect will fool my computer into behaving properly. Once I installed it, IntelliFIX retested my computer and reported that everything that previously failed had passed.

Is my second-string computer now saved? Perhaps. But IntelliFIX also identified several Y2K software problems that could upset the system even with the hardware fixed. Turns out that to be Y2K compliant, home PC users have to upgrade or replace their date-dependent software and inspect their databases for bugs as well.

Cunningham says your computer may operate even with these flaws, but once you've straightened out your hardware, you might as well visit Microsoft's Year 2000 Readiness Disclosure & Resource Center (http://www. microsoft.com/technet/year2k) to trouble-shoot your software. Most prone to problems: Data-based programs, money management programs and spreadsheets.

"There are fixes that even search your data, but the average home user wouldn't need that," says Cunningham, who recommends eliminating old and unnecessary databases rather than fixing them. "With the home consumer, this isn't going to be a catastrophe in most cases." Just an inconvenience.