Michael Dell is back as CEO of the troubled computer company that he founded and that still bears his name.

The company announced that Dell would immediately replace Kevin Rollins as CEO — the man Dell personally selected as his replacement in the chief executive's job back in 2004.

Dell Inc. had several notable stumbles during Rollins' leadership.

In 2006, there was the recall of millions of laptop batteries made by Sony because of their potential to cause a fire.

Last year also saw HP leapfrog over Dell as the world's biggest shipper of personal computers. Dell was also the only computer maker to see its U.S. sales fall in 2006.

And then there is the lingering matter of investigations into accounting irregularities at Dell Inc. by the U.S. Securities and Exchange Commission and the U.S. Justice Department.

The last straw appears to have been the company's announcement Wednesday that its fourth-quarter results would miss analysts' estimates. 

Dell shares, which have dropped by a sixth in the past year, rose by four per cent in after-hours trading.