It's every place in the world and it's nearly every product we sell

Chief financial officer Andy Bryant

Shares in Microsoft had earlier slipped more than 6% to $53.13 - wiping �20bn off its stock amrket value - after a Goldman Sachs analyst said poor PC sales would lead to lower profits and sales at the software giant.

Its shares have now fallen by about two thirds from the record highs hit at the end of last year.

Motorola and Apple

Intel also blamed several recent cancellations of large orders as the reasons behind its adjusted sales estimates.

Intel was the second large US firm to warn on Thursday of disappointing business performance after communications giant Motorola.

They followed a string of profit warnings in recent weeks from companies including Apple Computer, Hewlett-Packard, Gateway and Nortel Networks.

Intel said it now expected fourth-quarter revenue to be flat "plus or minus a couple of percentage points, with third-quarter revenue of $8.7bn".

Shares slump

Fourth-quarter revenue had been previously projected at 4-8% up on the third quarter.

Chief financial officer Andy Bryant said sales were slowing all over the world and in all products, with the exception of flash memory chips.

"What we believe is happening is a worldwide economic slowdown," he said.

"It's every place in the world and it's nearly every product we sell."

Intel shares slumped as low as $30 in electronic trading after the market's close. They had earlier ended the regular session at $32.31, just off a year's low and well down from the year's high of $75.81.