Apple Computer started its fightback yesterday against falling sales and heavy losses by announcing a revamp of its professional range of computers, new consumer-orientated software and a March release date for its long-awaited operating system, Mac OSX.

The announcements were made by the company's chief executive officer, Steve Jobs, to an adoring crowd of 5,000 people at the Macworld show in San Francisco.

The adulation could not hide the fact that Apple has been struggling recently. In December it forecast a loss for the first quarter of this year, the first since Mr Jobs returned in 1997 to the company he founded.

Industry researcher PC Data reported that Apple's US sales in the first half of December fell 40% against an industry-wide fall of 20%. Apple is expected to report this month a last quarter loss of $250m (£168m) due to disappointing sales of its new Cube desktop computer and its colourful iMac machine.

Yesterday Mr Jobs admitted: "The last few months have been particularly challenging for Apple and the rest of the industry," but added: "We've decided to start 2001 with a bang."

The most gasps were reserved for Mr Jobs's final announcement - a new ultra-thin PowerBook laptop computer called Titanium, the metal from which its case is made. The new machine is only 1in thick, weighs 5.3lb and sports a 15.2in display.

There were whoops of delight for a range of G4 machines which take the company's top-rated chip to 733MHz.

Perhaps more significant for Apple's long-term prospects was Mr Jobs's declaration of the company's vision, based around what he termed the "digital lifestyle". Included in his presentation was a trio of software packages: iMusic was presented as sophisticated software for handling digital music files, which Apple will give away from its website. He also announced iDVD, a new DVD creation program.