Shares of Hewlett-Packard Co. (NYSE: HPQ), the No. 1 computer company, set a new 52-week low of $16.77 on Thursday, after posting a record third-quarter loss last week and reducing earnings estimates for the current quarter.

HP shares closed $16.78, down 16 cents, lowering the value of the Palo Alto, Calif., company to only $33.1 billion, or nearly 36 percent below its value a year ago, a month before CEO Leo Apotheker was ousted and director Margaret (Meg) Whitman replaced him.

Overall U.S. markets fell about 1 percent, as did shares of most technology companies including Apple (Nasdaq: AAPL), the world's most valuable technology company and International Business Machines Corp. (NYSE: IBM).

Earlier Thursday, HP announced its re-entry into the tablet PC sector, which it exited a year ago, with plans to sell the HP Envy x2 model sometime in the fourth quarter.

HP's 52-week high was $30, set on Feb. 17.