It’s safe to say that Michael Dell probably isn’t having as much fun now as he did the first time ­he served as C.E.O.  Dell spent 20 years building ­his company, which he famously launched from ­his dorm room, into the world’s top computer seller. Along the way, he implemented superfast manufacturing techniques and perfected a strategy of selling directly to consumers. After he stepped down in 2004, the company went off the tracks, losing its reputation for quality and solid customer service. The stock, which had traded in the mid-$30s, lost about a third of its value.

Since returning 18 months ago, Dell has taken huge steps to turn the company around—some more successful than others. Recognizing that laptops now outsell desktops in the U.S. and that customers prefer to handle portable devices in person before buying, he updated the company’s sales strategy, striking deals to sell computers through chains such as Wal-Mart and Best Buy. At the same time, he shut down the Dell-branded kiosks that had opened in malls. (See a pop-up graphic showing where Dell is looking for new revenue.)

The company has also tried to spruce up its laptop designs, with mixed ­results: Customers in Europe recently received laptops with mutant keyboards—one key was in the wrong position. And with the U.S. market maturing, Dell is making a big push to increase its market share overseas, where it generates about half of its sales already. (One unscientific indicator, though, suggests that he still has work to do: At a Shanghai electronics store, a salesman enthusiastically recommended a Lenovo laptop and a Hewlett-Packard before finally suggesting a Dell.)

The company plans to introduce ­a new line of subnotebook computers ­(a cross between laptops and palmtops), some of which may even be pre­installed with Linux, an operating system that competes with Microsoft’s Vista. This would be a thumb in the eye of Microsoft, one of Dell’s major partners.

Dell talked with Condé Nast Portfolio senior writer Russ Mitchell in Shanghai.

What’s the real reason you came back as C.E.O.? Revenge! I started the company, so it’s my child. I feel responsible for it.

Who would you be vengeful toward? I’m half joking. But this is a company that in 12 years grew from $5 billion to $61 billion. That doesn’t happen very often. But it’s fair to say that it wasn’t working as well at the end of that time as it had been at the beginning. I was watching that happen as chairman, and it wasn’t particularly satisfying. So I was happy to come back into the job I’d had for 20 years. Last year, we reprioritized, made all sorts of investments, wrote off a bunch of things, and still managed to grow our earnings 15 percent and make $2.9 billion in profit.

What brings you to Shanghai? China is the second-largest country in the world for Dell sales, and it’s growing fast. We can see forward to when it’s going to be the largest. Last quarter, our unit sales here—meaning the ­number of machines rather than a dollar amount—grew 51 percent. The rest of the industry grew 18.5 percent here. So that’s a pretty tempting reason to come.

You’re also making major efforts in Israel and the Middle East. All through the Middle East, the former Soviet republics, even all of Africa, there’s enormous growth in I.T.  We’re focused on the next billion computer users, and they’re not in the developed countries. All you have to do to find them is figure out where there are people with cell phones. Because once they get a cell phone, about a year or two later they want a computer.

Does that mean you’re giving up on the United States? No. The U.S. market is still the biggest in the world. But you’re not going to get another billion users in the United States.