Hewlett-Packard shocked Wall Street Thursday by announcing disappointing sales and profits even as some of its top competitors are thriving. HP Chief Executive Carly Fiorina blamed a series of internal missteps for the shortfall, which she called ``unacceptable.'' She immediately fired three top executives. But some analysts said the poor performance reflected deeper problems raised by HP's $19 billion purchase of Compaq Computer two years ago. In a conference call with investors, Fiorina said, ``Execution issues cost us and therefore we are making immediate management changes.'' The financial bombshell came a week before the company was scheduled to release its...