Despite a corporate spying scandal that forced the resignation of its chairwoman, Hewlett-Packard Co. yesterday said fourth-quarter profits quadrupled as it surpassed Dell Inc. as the world's biggest personal computer maker.

The better-than-expected earnings reassured Wall Street that the distractions of the past quarter — including criminal charges against former chairwoman Patricia Dunn — did not interfere with business. But as HP approaches $100 billion in annual sales, Chief Executive Mark Hurd warned that growth rates may be hard to sustain.

Shares rose 34 cents to $40.16, but fell 28 cents to $39.86 in late trading after the earnings were released.

The Palo Alto, Calif., company reported net income of $1.7 billion, or 60 cents a share, up from $416 million or 14 cents, a year earlier, when HP took a restructuring charge of $1.1 billion. Sales rose 7 percent to $24.6 billion.

Long dominant in printers, HP reclaimed the mantle of top PC maker for the first time since 2003, as the company capitalized on the rise in purchases by home users. Sales of notebook computers, in particular, rose 24 percent over last year. Sales of desktop machines were flat and sales to commercial clients rose just 4 percent.

"We continue to believe HP has an advantage in the consumer market as customers prefer to buy laptops at a store, rather than online," wrote Benjamin A. Reitzes, an analyst for UBS Investment Research, in a research report Monday.

Reitzes said an HP program that allows customers at Wal-Mart stores to configure their own computer system will buoy low-end sales.

HP rival Dell, which sells its computers online and by phone, has seen its margins and market share shrink amid a slowing in corporate purchases. Dell delayed reporting quarterly results scheduled for yesterday because of an investigation into the company's accounting by the U.S. Securities and Exchange Commission.

With one-time charges excluded, HP would have earned 68 cents per share for the quarter ending Oct. 31. Analysts surveyed by Thomson Financial expected 64 cents.

For fiscal year 2006, HP reported net income of nearly $6.2 billion or $2.18 a share, up from $2.4 billion or 82 cents a share a year ago. Sales for fiscal year 2006 rose 7 percent to $91.7 billion.