Shares of Dell (Nasdaq: DELL), the No. 3 PC maker, plunged more than 5 percent after the company reported poor second-quarter results and issued a forecast for lower sales ahead. In pre-market trading, shares fell as low as $11.72, down 62 cents.

The Round Rock, Tex., PC and services provider reported second-quarter net income dropped to only $732 million, or 50 cents a share, on an 8 percent revenue fall to $14.5 billion. On an investor call Tuesday, Chairman Michael Dell and CFO Brian Gladden said the second half of the fiscal year will be challenging because businesses are taking "a wait and see approach" to ordering PCs and tablets.

Dell plans to introduce a tablet based on the RT OS from Microsoft (Nasdaq: MSFT), the world's biggest software company, which use chips from Arm Holdings (Nasdaq: ARMH) of the U.K., which also run the iPad from Apple (Nasdaq: AAPL), the world's most valuable technology company.

Separately, shares of Hewlett-Packard Co. (NYSE: HPQ), the top PC maker, fell more than 2 percent early Wednesday. The company is scheduled to report results after the markets close.

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