By BBC News Online's Ivan Noble at CeBIT 2002 in Hanover

The chief executive of software giant Microsoft opened the world's largest technology fair in Hanover on Tuesday with a promise of better behaviour towards competitors and governments.

I am sure that this CeBIT will send a signal of confidence and a new start

Chancellor Schroeder

Steve Ballmer was sharing the platform with German Chancellor Gerhard Schroeder when he acknowledged his company had a less than perfect track record as far as trustworthiness went.

"We need to be a responsible leader for our industry," he said. "We have to be a respectful, open and appropriate competitor."

Hundreds of thousands of visitors are expected at the CeBIT show over the next few days amid hopes the products on display could help spark a recovery in a sector hard hit by an economic downturn.

German campaign

Microsoft has a longstanding dispute with the authorities in the US over its anti-competitive behaviour and now faces legal action for damages by a competitor, Sun Microsystems.

On show: Siemens' new SX45, a colour-display pocket PC that is also a mobile phone

And in Germany, a high-profile campaign has sought with some success to persuade the German parliament to replace Microsoft Windows on its own servers with free, open-source alternatives like Linux.

Mr Ballmer said Microsoft wanted greater involvement with governments and recognised that there were many policy issues to be resolved.

Both he and Chancellor Schroeder were keen to point out the need for better computer security in the wake of the attacks in the United States on 11 September.

Security call

"Not just since 11 September has security technology in all its aspects been at the top of the shopping list of companies and authorities," Chancellor Schroeder told the CeBIT gathering.

Both he and Mr Ballmer were unreserved in their optimism about the future of the technology industry two years after its boom began to collapse.

"I am sure that this CeBIT will send a signal of confidence and a new start," he said, adding to the Microsoft chief's statement that the industry would do more to "positively impact" the world in the next 10 years than in the last.

Microsoft is in Hanover to present more of the technology it hopes will link mobile users into its .Net plan to dominate business on the internet.

And its Xbox games console makes its European debut on Thursday.

BBC News Interactive will be reporting daily from the world's largest technology fair and will have a special report on Microsoft's efforts to extend its success with Windows to mobile computing.