DALLAS (AP) _ Shares of Dell Computer Corp. fell 19 percent in trading Friday after the nation's largest computer maker warned that revenues next year would increase only 20 percent, lower than expected.

Dell's announcement late Thursday came as the Round Rock-based company said third-quarter operating earnings grew 40 percent despite slowing growth in personal computer sales.

Though the results met the earnings expectations of analysts surveyed by First Call/Thomson Financial, investors focused on the revenue forecast.

Dell shares fell $5.38 to close at $23 Friday on the Nasdaq Stock Market.

Several analysts downgraded Dell early Friday, including Banc of America Securities and Morgan Stanley Dean Witter.

Gillian Munson, a Morgan Stanley Dean Witter analyst, said she had expected 24 percent revenue growth next year. She said Dell, which has missed or lowered its financial targets in four of the last five quarters, would need time to regain investor confidence.

Kurtis King, an analyst for Banc of America Securities, said competitors, notably Houston-based Compaq Computer Corp., have cut into Dell's revenue growth.

In the first quarter, when Compaq was struggling to post a 1 percent year-over-year gain in revenue, Dell's revenue was jumping 32 percent. By the third quarter, Compaq had recovered to 22 percent revenue growth, matching a slower Dell.

King said Dell could find it difficult to return to its earlier, faster growth.

Dell officials told analysts Thursday night that they could strike back at competitors by being more aggressive on price _ they said falling costs for computer components would allow them to cut product prices without sacrificing profit margins. But King said competitors could do the same thing.

Some analysts applauded the company for emphasizing sales of higher-priced servers, notebook computers and services. Third-quarter sales of enterprise products grew 37 percent and notebook sales jumped 45 percent, officials said.

Don Young, a UBS Warburg analyst, said Dell's shift to servers and notebooks is more attractive in the long run than continuing to rely on the commodity-like PC market.

But Munson, of Morgan Stanley Dean Witter, said she was concerned Dell would have to invest heavily for some time to make its servers and services stand out from competitor's products. Companies that compete in those high-end markets, such as IBM, Hewlett-Packard and Sun Microsystems, invest a far greater share of their revenue in order to make successful products, she said.

While investors have worried about the impact of slowing PC sales on Dell, not all analysts see trouble for Dell in that market. Kurt Schlegel of Meta Group said sales of Microsoft Corp.'s new Windows 2000 operating system would boost sales of PCs to businesses.

Dell reported late Thursday that its third-quarter net income was $674 million, or 25 cents per share, up from $289 million, or 11 cents per share a year earlier. The year-ago figures include a charge of $194 million, or 7 cents a share from the purchase of ConvergeNet Technologies Inc; excluding the charge, Dell had operating earnings of $483 million, or 18 cents per share.

Dell vice chairman Kevin B. Rollins said in an interview that the company is still on target for $32 billion in revenue this year and fourth-quarter earnings of 28 cents per share.