Dell, whose shares fell as much as 5.1 percent in after-hours trade, also said it would take charges of about $450 million in the third quarter for costs of repairing some computer systems for customers, cutting jobs and restructuring units.
The company in August missed analysts' second-quarter revenue growth forecasts because it lowered prices aggressively on its entry-level US personal computers.
Dell, based in Round Rock, Texas, said it expects fiscal third-quarter profit per share of 39 cents before one-time items, missing analysts' average estimate of 40 cents per share, according to Reuters Estimates.
The $450 million charge cuts net income by a further 14 cents per share to 25 cents.
The company said it expects to report revenue of $13.9 billion, below its earlier forecast of $14.1 billion to $14.5 billion and analysts' $14.3 billion estimate. US consumer and British unit sales "fell short of expectations," Dell said.
"They were seeing some weakness in desktop and strength in notebooks, but not enough to offset the weakness in desktop," analyst Shaw Wu of American Technology Research said after Dell's announcement. "Dell's problem is that it's not differentiated enough" from competitors.
Dell had earlier forecast third-quarter earnings per share of 39 cents to 41 cents before items.
The company said $300 million of the charge was due to repairing systems that included a part from a vendor that did not perform to Dell's specifications.
The problem affects "a small percentage" of older OptiPlex desktop systems used by businesses, Dell said. Charges also cover the costs to cut an unspecified number of jobs in Texas and the UK, spokesman Jess Blackburn said by phone. A "very limited" number of jobs were cut in the Asia-Pacific region, he said.
"It's a very small percentage of our overall workforce that was impacted," Blackburn said, adding that the cuts were made last week.
The technical problem involves potentially faulty capacitors on Dell's GX270 and GX280 desktops used by business customers, Blackburn said. He declined to name the company that supplied the capacitors, which are on the computers' motherboards, the chassis on which computer components are assembled. No recall has been announced, he said.