Michael Dell replaced Kevin Rollins as chief executive officer of Dell today.
The move comes as the world's number two PC maker struggles in the US consumer market and suffers market share losses to Hewlett-Packard.
The company warned this quarter's results would fall below analyst estimates, in the latest sign of the challenge it faces from HP and tough pricing competition in the industry.
Mr Dell started the company in 1984 in his university dorm room with $1,000, and made it a PC powerhouse. But results have been uneven since Mr Rollins took over in July 2004, analysts said.
News of Mr Dell's return lifted the stock by nearly 5 per cent, in hopes he would reinvigorate the company.
But Mr Dell gave no specific plan for how to mould it into what he calls "Dell 2.0," and he and Mr Rollins have long said they ran Dell together.
The founder, whose 10 per cent stake in Dell is worth about $5.5 billion, pioneered a "build-to-order" model in the personal computer industry, leading it to become top-ranked PC maker at one stage.
