The new millennium dawned this morning and the world's computers hummed along as if it were just another day, the feared Y2K bug barely noticeable.

Only a few sporadic glitches popped up today, while experts warned that it could take days, weeks or months before problems are discovered.

From nuclear power plants to ATMs to airplanes, few problems surfaced immediately as the year 2000 began in the South Pacific and swept west.

"The Mouse That Didn't Roar," read a headline in today's Bangkok Post.

Still, the millennial bug -- a simple computer glitch when the date changes from 1999 to 2000 -- was responsible for a few problems.

A computer linked to radiation monitoring devices at a Japanese nuclear plant failed, but officials said it wasn't considered serious enough to shut the plant. Ticketing machines on some buses in Australia briefly jammed. Forecasting maps at the French weather service initially got the New Year Day date as "01/01/19100." Eight hundred slot machines shut down at a Delaware horse track.

Unrelated to Y2K, U.S. nuclear power plants in Pennsylvania and South Carolina were shut down and a third had trouble with a scheduled startup as the new year approached, officials said. A glitch sent clocks at eight U.S. utilities racing ahead. Officials quickly fixed them.

But the problems didn't compare to the dire predictions that spurred years of preparations and an estimated $500 billion spent worldwide to avoid the worst.

Experts said the time and money was worth it.

"The reason we're in the position we're in is because we spent that money. Had we not spent this money, we would be facing worldwide calamity," said Matt Hotle, vice president of the technology consulting firm Gartner Group.

And they warned that though it appeared to be much ado about nothing, there remained a potential for damage.

"It's always dangerous in the first several hours after an event to be drawing firm conclusions about what's happened. I personally would like to wait a couple of days," said Norman Dean, executive director for the Center for Y2K and Society in Washington.

In Asia, Africa, Eastern Europe and other parts of the world considered most at risk for Y2K meltdowns, officials reported no problems.

Computer experts might have overestimated the risk in developing countries, basing their predictions on anecdotal information, Hotle said. "We didn't know what technology was there," he said.

Russian nuclear weapons sites and the country's 29 nuclear reactors, which rely on clumsy Soviet-era technology, suffered no problems. Aging atomic power plants ran without a hitch in Ukraine, which in 1986 suffered the world's worst nuclear disaster with a meltdown in Chernobyl.

The bug was quiet in Western Europe and Africa. Italy, one of the worst-prepared countries in the West, started the new century without trouble.

"I feel like I should be reporting something dramatic, but I'm afraid I can't," said Ian Macfarlane, governor of Australia's central bank. He was almost apologetic as he announced no problems with his country's financial system.

A Y2K glitch in Japan caused vending machines for prepaid train cards to stop working briefly in 13 stations. Phones, electricity and ATMs worked fine in Croatia, though the free phone line to answer Y2K questions was disconnnected. Tamil separatists in Sri Lanka posted a notice on their Web site saying they were Y2K compliant.

As the countdown ticked off before the midnight hour, many countries shut down vital systems to be safe. Airports in several countries canceled flights. Subways in Cairo and Istanbul were closed. Large ships were banned from the Bosporus strait. ATMs in Beijing were shut. Indonesia cut oil production.

In the United States, the bug caused barely a ripple: Banking, energy, transit and communications systems all suffered no breakdowns.

Elsewhere, some of the world's best-known pieces of machinery survived the turnover completely unaffected by the Y2K computer glitch -- since they don't use computers.

Old-fashioned clockworks let Big Ben chime in the new year in London, while the Panama Canal let ships through its mechanically operated locks. The United States returned the waterway to Panama's rule on New Year's Eve.

And while most people were calm, many people stockpiled food, cash, gasoline and other essentials, anticipating the crash of an increasingly computerized world.

"It was all nonsense," said Jerome Robbins, a mechanic in Kingston, Jamaica who took his family to see the fireworks over the city's harbor. "People just making a fuss about nothing, nothing at all."