By Rex Crum, MarketWatch SAN FRANCISCO (MarketWatch) -- Big declines from NetApp Inc. highlighted a swath of losses across the tech sector Thursday, sending nearly every major tech stock into the red and putting even more pressure on Hewlett-Packard Co. and its upcoming quarterly earnings report. The losses helped drag down the Nasdaq Composite Index (RIXF) by 116 points, or 4.6%, to 2,395. The Philadelphia Semiconductor Index (SOX) was down by more than 5% and the Morgan Stanley High Tech 35 Index (MSH) gave up 6%. NetApp (NTAP) shares plunged by $8.10, or 19%, to $33.79 after the data-storage technology company gave a disappointing quarterly report and outlook. Late Wednesday, NetApp reported a fiscal first-quarter profit of $139.5 million, or 34 cents a share, compared with a profit of $150.7 million, or 40 cents a share, for the same period a year ago. Revenue rose to $1.46 billion from last year's sales of $1.15 billion. Excluding one-time items, NetApp would have earned 55 cents a share, which met the forecast of analysts surveyed by FactSet Research, who also pegged NetApp's quarterly revenue at $1.5 billion. Steve Gomo, NetApp's outgoing chief financial officer, said the company saw a "dramatic slowdown" in sales during July. NetApp also gave a second-quarter forecast that fell short of analysts' estimates. With NetApp in the lead, other data-storage company's shares also retreated. NetApp's biggest rival, EMC Corp. (EMC), was down by $2.38 a share, or 10.5%, at $20.13, hard disk-drive makers Seagate Technology (STX) fell 9.6% and Western Digital Corp. (WDC) was off by 9%, Brocade Communications Systems Inc. (BRCD) ga ve up 8% and electronics contract manufacturer Jabil Circuit Inc. (JBL) saw its shares fall by 11%. Dell Inc. (DELL) gave up 4.6% to fall to $13.55 after shedding 10% on Wednesday on reaction to the PC company cutting its full-year forecast. H-P (HPQ), which is set to report quarterly results after the market close, fell $2.39 a share, or 7.6%, to $29.02.