In line with a strategic realignment towards software and solutions for businesses, the Palo Alto, California-based HP also announced it was buying British enterprise software company Autonomy for $10.24 billion.
HP said it will purchase all of the outstanding shares of Autonomy for $42.11 (£25.50) per share in cash, a premium of 64 percent over Autonomy's closing price on the London Stock Exchange on Wednesday.
It said the deal had been unanimously approved by the boards of directors of both companies and should be completed by the end of the year.
In a further move away from the consumer space, HP said that it was stopping production of its TouchPad tablet computer, its rival to Apple's iPad which was introduced just seven weeks ago, and phones based on the webOS mobile operating system acquired from Palm last year for $1.2 billion.
HP shares lost 5.99 percent on Wall Street on Thursday to close at $29.51 and shed another nine percent in after-hours electronic trading following the series of block-buster announcements.
HP's low-margin PC business has been the subject of separation rumors for months and HP shares have slumped this year amid investor concerns that the company is being overtaken by younger, nimbler Asian rivals.
Leo Apotheker, a former top executive of German business software giant SAP who took over as HP's chief executive in November, said the moves were part of a "transformation to position HP for a new future."
"The transformation starts today," Apotheker told financial analysts.
Explaining the decision to sell or spin off the PC business within the next 12 to 18 months, the HP CEO said the weak economy was having an impact on PC sales but there is also a "clear secular movement in the consumer PC space."
"Consumers are changing their use of the PC," Apotheker said. "The tablet effect is real and sales of the TouchPad are not meeting our expectations."
"For our PC business to remain the world's largest personal computing business it needs the flexibility and agility to make decisions best for its future direction," he said.
The PC market has been flat amid an explosion of powerful smartphones and the arrival of hot-selling tablets such as the iPad.
Apotheker said HP was mulling various options for the webOS software acquired from Palm including licensing the platform for use by third-party manufacturers.
HP said revenue declined three percent at its personal computer division last quarter with a 5.9 percent operating margin. It said commercial client revenue grew nine percent and consumer client revenue fell 17 percent.
While separating from its PC unit, Apotheker said HP intended to retain its profitable printing business which has significant commercial applications.
Shortly after taking over, Apotheker said he planned to refocus the company on software and technology solutions and make a major push into cloud services -- offering applications and storing data over the Internet.
The purchase of Autonomy, which was founded in 1996 and makes software for companies to search and manage huge databases, fits the strategy of "building a successful software business," he said.
"Autonomy brings to HP higher value business solutions that will help customers manage the explosion of information," he said.
"Autonomy has an attractive business model, including a strong cloud based solution set, which is aligned with HP's efforts to improve our portfolio mix."
Technology analysts said HP's decision to abandon its PC unit recalls that of US computer giant IBM, which sold its PC business to China's Lenovo in 2004 for $1.25 billion.
Gartner analyst Mark Margevicius cautioned, however, that "we're not in an era when the PC is dead.
"The PC market is flat but it's still a huge business," Margevicius said.
It remains HP's largest single revenue generator, but it "just doesn't produce all that much profit," he said. "The PC market has transformed into a tactical, commoditized business.
"HP, as a vendor, has many, many things within its coffers to sell to its customers. It sells services, it sells online stuff, it's got networking stuff, it's got software," he said.
"It's got all kinds of other things that from a business point of view make far better margins and profit than does the PC business," Margevicius said.
"If the PC business was a business that generated 20 percent margins, HP's not dumping their PC business," the Gartner analyst said.
