By the BBC's Kevin Anderson

The United States, the most-technology dependent country in the world, escaped major disruption from the Y2K computer bug.

US corporations and the government spent an estimated $100bn to make computer systems ready for the new year and was about half the amount the entire world spent tackling the problem.

But the effort was so successful that those in government and private industry are on the defensive.

The US experienced few computer glitches as the world rang in the New Year. But a few did surface:

• At least eight power stations in the Midwest had to reset their clocks when they jumped ahead by as much as 35 hours when they briefly lost contact with global positioning satellites.
  
  
• The Defense Department lost the ability to process information from some of its spy satellites on Friday night for two to three hours, but the spy satellites themselves continued to function.
  
  Some service was restored immediately but the problem was not completely fixed until Monday.
  
  
• A few hundred slot machines at racetracks in Delaware were hit by the glitch, making them inoperable for 24 hours.
  
  
• A New York video store charged a customer a $91,000 late fee because the store's computers thought the video had been out since 1900.

Y2K experts defensive

It was feared that computers using just two digits to represent the year in dates might confuse '00' as 1900 instead of 2000 causing them to malfunction or stop working completely.

But as with most places in the world, the lights stayed on in the US, the missiles stayed in their silos and everyone was able to get money from their cash machines.

However, this was the case with much of the world even in places that started working on the problem much later than the US and spent much less.

John Koskinen, who headed the US effort to respond to the problem might be a victim of his own success.

Speaking from a $50m command centre established by the White House, he said: "We geared up for a major potential set of problems and I think all of us view it as a great victory that we can sit here and talk about, 'Was it money well spent? Did we have to do it?'"

Mr Koskinen defended the more than $8bn the US Government spent to fix the problem, which was $5bn more than the first estimate of the cost of repairs and contingency plans.

He said that as much as $10bn may have been spent needlessly in the US since 1995 as "somebody may have bought something they didn't need or figured it was a great way to get a replacement system".

But in response to those who say consultants and companies selling Y2K fixes might have overstated the problem for profit, Mr Koskinen said, "corporations don't naively spend hundreds of millions of dollars".