Advancing for a fourth straight day, the Dow Jones Industrial Average (DJINDICES:^DJI) responded kindly to falling jobless claims. Despite the undeniable bullishness of the stock market, the labor market remains an area of serious concern -- the unemployment rate stood at 7.6% in February. So Wall Street cheered the slipping jobless claims Thursday, as the Dow added 52 points, or 0.4%, to end at 14,865, an all-time record close.

Within the index, Pfizer (NYSE:PFE) boasts some serious momentum of its own. The drug maker started rallying yesterday on news the FDA granted "breakthrough" status to a breast cancer drug, ensuring a more timely review process. The promising treatment, palbociclib, is in phase III trials, and the FDA announcement sent Pfizer 2.3% higher to 52-week highs today.

But, strangely enough, bearishness in the tech sector really defined the day. Hewlett-Packard (NYSE:HPQ) led the laggards with 6.9% losses. The catalyst was a serious one: Research firm IDC reported the largest year-over-year quarterly drop in PC shipments ever. HP can find solace in the fact that it's still No. 1 in overall shipments, but being No. 1 in a market that's imploding isn't much to be proud of.

Microsoft (NASDAQ:MSFT) also got hit big from the news, cratering 4.8%. The miserable numbers have obvious consequences for the Windows operating system, and they show Windows 8 has failed to catch on with consumers. This puts major pressure on Microsoft to succeed in the emerging tablet and mobile device markets.

Lastly, Intel (NASDAQ:INTC) shares also suffered the effects of the 14% decrease in PC sales, losing 2.5% today. Unfortunately Intel got simultaneously hit by an analyst downgrade, citing the bleak PC outlook. It doesn't help, as the Argus Research analyst noted, that CEO Paul Otellini is leaving the company, and no one's quite sure who's replacing him.

Fool contributor John Divine has no position in any stocks mentioned. You can follow him on Twitter @divinebizkid and on Motley Fool CAPS @TMFDivine.

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