SAN FRANCISCO -- After seeing sales stagnate for nearly two years, Dell ( DELL) is set to resume its growth.

At least that's what Wall Street is expecting, given the average analyst estimate that the PC maker's fiscal fourth-quarter revenue increased at a double-digit clip.

Whether or not this growth represents the fruits of a comeback or simply reflects an easy year-on-year comparison should become more clear when Dell reports earnings after Thursday's market close.

Since Michael Dell returned to the CEO spot in January 2007, the company has overhauled many long-time pillars of its business model.

Dell PCs are now available in retail stores like Wal-Mart ( WMT), Best Buy ( BBY) and Staples ( SPLS), with an eye on the consumer -- a striking departure from Dell's previous strategy of selling exclusively through Internet and phone orders as it primarily courted corporate customers.

And the company has made a string of acquisitions, the majority intended to bolster Dell's growing services business.

But investors, already nervous about the prospects of tech companies in a slowing economy, are waiting for Dell's various new initiatives to yield tangible results: Dell's stock is down 26% since November.

"There are a lot of skeptics out there on Dell. The turnaround has not happened overnight," says Pacific Crest Securities analyst Brent Bracelin.

Indeed, as recently as the third quarter, Dell's results offered more fodder for worry than inspiration. The company's third-quarter gross margin was down, operating expenses were up, and sales of Dell's consumer PCs fell 6% year over year.

Despite the bumpy road, Bracelin believes Dell is now repositioned for growth, and expects the numbers in the fourth quarter to begin moving in the right direction.

Analysts polled by Thomson Financial expect Dell to earn 36 cents a share in the fourth quarter, with sales of $16.2 billion -- up 12.5% year-over-year. That's not too spectacular a feat, given how weak sales were in the year-ago period, but it still represents Dell's fastest growth since the fourth quarter of 2005.

American Technology Research analyst Shaw Wu believes Dell could actually beat the Street's top- and bottom-line expectations for the fourth quarter. He notes that the average analyst estimate calls for Dell's sales to grow only 3.9% sequentially, slower than the 4.9% rate he says is normal for this time of year.

Yet even as Dell moves ahead with its comeback plan, it does so against the backdrop of a worsening economic climate.

Industrywide PC shipments were strong in the fourth quarter, growing 15.5% year over year according to research firm IDC. But Dell may not be able to count on such robust demand going forward.

On Wednesday, JP Morgan analyst Christopher Danely issued a note to investors warning of decelerating PC demand, citing rising microprocessor stockpiles across the industry.

Dell has taken much-needed steps to fix its competitive shortcomings. Whether that can save the company from a prolonged slump in demand is another story.