The computer experts and crisis management officials in Fairfax and Arlington counties and Alexandria have one message for you as the clock ticks toward the first minutes of the next millennium: Don't worry.

Officials in all three jurisdictions say they are 100 percent certain that no major problems will cause chaos next week. They've checked and rechecked their systems, they say. And just to be safe, they've got a virtual army of computer programmers, police officers and others standing by.

"We have gone through our programs and we are confident that what we have done is 100 percent compliant," said Fairfax County's chief information officer, David Molchany. "We started our preparations in 1996. We are confident. If something happens, we'll go to plan B, and we'll just deal with it."

Fairfax has spent $3.63 million to fix the glitch that could cause computers to malfunction on Jan. 1. The county either replaced or revamped every system, including the computers that handle taxes, payroll, social services, Circuit Court, public works and land use.

As the last days of 1999 approach, the county is even fixing the last few desktop computers--a task not considered critical for the operation of the county. But Molchany said they might as well fix the nonessential problems because they're done fixing the essential ones.

"This has been a great experience," he said. "It really gave us an opportunity to look at our systems and see which ones we want to fix and which we want to replace."

And yet, even with 100 percent certainty, the county is not resting on its laurels. County officials are making massive emergency preparations--just in case:

* Portable generators are being set up to handle power at the jail, the juvenile detention center and other critical county buildings in the event of a massive power outage.

* Police and fire officials will carry non-satellite-dependent pagers for communication, in the event the satellites that carry the nation's wireless signals go haywire. Every one of the county's police officers and firefighters either will be working or on call on New Year's Eve.

* About 100 of the county's top officials began gathering each day at a disaster operations center in Annandale, starting Monday. All together, about 1,500 county employees will be working on Jan. 1 and another 2,000 will be on call.

* Thirty of the county's computer programmers and data specialists will be on duty that night, prepared to work their magic if the Y2K glitch somehow hits systems that were deemed to be fixed, or if computers fail for other reasons not related to the famous computer problem.

"As we get those calls, we will handle them as we handle any trouble call, whether they are Y2K or not is not going to make much difference," Molchany said, noting that computer technicians are used to dealing with unwanted glitches. "The thing that has been forgotten is that we are always on call."

In Arlington County, officials are fairly confident that they are ready to face the enemy--Dec. 31--one year and $21.5 million after starting their Y2K preparations.

"We are Y2K compliant," County Manager William J. Donahue told the Arlington County Board at a recent meeting. "We do not expect any Y2K problems. The public should view our extra staffing as contingent in nature."

That extra staffing numbers 500, including the entire county police force and an additional 25 fire personnel beyond the usual number. The command center, at Courthouse West, will be home to roughly 100 county employees New Year's Eve, including the fire and police chiefs, the superintendent of schools and the county manager. The projected overtime cost will be $40,000.

Among the county's preparations this year were a complete overhaul of its traffic-light system and corrections to the computers to ensure they continue to function once the clock strikes midnight. In September, in conjunction with the Metropolitan Council of Governments, the county ran a dress rehearsal and declared all systems go.

"We are pretty well done," Assistant County Manager Richard Bridges declared last week.

Nonetheless, said Bridges, a retired Army colonel, the county has ongoing preparations and emergency systems in place because "the more you prepare for something to happen, the less likely it will."

In the case of telephone failure, county personnel will be on hand in county government cars at every fire station and another 23 locations--33 sites in all--to assist residents if needed.

Next door in Alexandria, Y2K preparations began more than a decade ago, in effect, because it was in 1987 that the city began a complete overhaul of its computer system, making each machine ready for the year 2000 as it went.

The city's emergency command center will be at the Lee Center, staffed by about 30 individuals including numerous city officials and department heads. Citywide, about 200 employees will be on duty.

The city will have two sets of payroll checks sealed away in its vault, on the off-chance that the payroll system breaks down. Apart from the possibility of minor glitches, one of which could affect a portion of the parking ticket system, city officials believe all systems are go.

"We're confident that we're in good shape," said Mark Jinks, director of financial and information technology services.

Despite the confident postures, officials still have nightmare scenarios of what could go wrong.

In Arlington, one is that people will overload 911 with frivolous calls, rather than using the county's two nonemergency numbers: 703-228-3000 for general information, and 703-558-2222 for nonemergency fire, medical or police issues.

In Alexandria, one fear is of weather problems.

The weather "can be a doubled-edged sword," Fire Chief Tom Hawkins said. "It could be you end up with a couple thousand people at the [National] Mall and there's an ice storm and they can't get home. The other side of coin, is that, if horrible weather is predicted, most people won't go in the first place."

JUST IN CASE

A Checklist of Y2K Helpful Hints and Phone Numbers

If the new year brings problems to Northern Virginia, here is a list of places to go and phone numbers to call.

Alexandria: 703-548-6257.

Arlington: 703-228-3000 or 703-558-2222 (non-emergency public-safety number).

Fairfax County: 703-691-2131 (non-emergency public-safety number).

Falls Church: 703-248-5200 or 703-248-5062 (police non-emergency number).

If telephone service fails, Arlington County will have personnel with cell phones in 33 positions throughout the county available to help residents. To find the location nearest them, residents can call 703-228-3000.

What supplies should you have on hand in case there are Y2K problems? The same food and equipment you would keep for a weather emergency, according to federal Y2K experts, as well as up-to-date financial and medical records.

* Bottled water (a gallon a person a day).

* At least three days' worth of nonperishable, ready-to-eat food.

* Flashlights, battery-operated radio, extra batteries.

* Extra supplies for infants, the elderly or others with special needs.

* More than half a tank of gas in cars.

* Enough cash for a couple of days. But not too much, because of the risk of theft.

* Check with manufacturers whether computers, security systems, programmable thermostats and other home equipment are Y2K-compatible.

* More information is available on the Internet at www.y2k.gov.

SOURCE: Federal Emergency Management Agency, President's Council on Y2K Conversion.