(Updated from 7:25 p.m. EST)

If misery loves company, then beleaguered boxmakers

Apple

(AAPL) - Get Report

,

Dell Computer

(DELL) - Get Report

and

Gateway

(GTW)

found a new friend tonight. After the closing bell,

Compaq

(CPQ)

became the latest PC manufacturer to issue a profit warning.

As a result, shares of Compaq decreased 4.9%, to $19.75, in extended trading on

Instinet

, having dropped as low as $19.50 earlier in the post-close session.

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This evening, Compaq said that revenue and earnings for the fourth quarter ending Dec. 31 would fall below Wall Street's expectations. The boxmaker expects to post revenue of $11.2 billion to $11.4 billion, compared to Wall Street's prediction of $12.31 billion.

The boxmaker forecasts earnings from operations, excluding charges, to fall between 28 cents and 30 cents a share. Analysts, according to

First Call/Thomson Financial

, expected the company to earn 36 cents a share. Compaq will also make downward adjustments in the valuations of some of its Internet-related businesses, specifically

CMGI

(CMGI)

, and take a non-operating, non-cash charge for the fourth quarter.

"While we had a good start to the fourth quarter, it is now clear that market confidence has wavered and that we will be affected by the general softness in U.S. consumer, small and medium-businesses and dot-com markets. Business activity in the rest of the world remains on track," said Compaq CEO Michael Capellas. (

TheStreet.com

discussed Compaq's

warning in a separate story.)

The selling pressure on Compaq spilled over to Dell, which warned about its fourth-quarter profit margins back in November. Dell stock lost 3.2%, to $21, on Instinet and lowered 3.5%, to $20.94, on Island, and was both platforms' most active stock. Other PC makers to have warned, Gateway and Apple, remained unchanged from their closing prices of $17.60 and $15.38, respectively, on Instinet.

Hewlett-Packard

(HWP)

, meantime, fell 1.4%, to $34.75 on Instinet.

In other company news, Internet consulting firm

Razorfish

(RAZF)

announced that it expects to post lower-than-expected revenue and losses, because of adverse macroeconomic conditions. As a result, shares of Razorfish plunged 27.3%, to $2.25, on Island.

Razorfish said that it expects to post a loss anywhere from 17 cents to 22 cents per share, compared with Wall Street's prediction that the company would report a 2-cent profit. The consulting firm forecasts revenue of around $50 million, which falls below analysts' prediction of $82.7 million.

Elsewhere, telecommunications company

Net2Phone

(NTOP)

gave post-close investors a reason to buy. The company posted a narrower-than-expected first-quarter loss, sending its stock up 32.3%, to $12.90, on Island. In addition, Net2Phone said that its number of paid subscribers increased to 1.8 million from 390,000 last year.

Net2Phone posted a first-quarter loss of 25 cents per share, compared with a loss of 11 cents a share in the year-ago period. Wall Street analysts polled by

First Call/Thomson Financial

expected a loss of 30 cents a share. In addition, Net2Phone reported revenue of $30.8 million, compared with $13.1 million in the same period last year.

Because so much bad news has already been priced into the market, the most high-profile preannouncements made after the closing bell have failed to topple companies' stock performances the next day. While Compaq's warning would ordinarily shake the market tomorrow morning, a glance at the futures market indicates that probably won't happen.

At last look, the

S&P 500 futures on

Globex

were down 1, to 1399.2, about two points below

fair value and indicating a positive open for Wednesday's start. The

Nasdaq 100 Securities

were behind 16.5 to 3016, about 16 points below fair value and showing upward pressure for the Nasdaq's open tomorrow.

This information is provided by Instinet, a wholly owned subsidiary of Reuters (RTRSY) . For further information, please contact Instinet at www.instinet.com.

Island ECN, owned by Datek Online, offers trading, mainly in Nasdaq-listed stocks, from 7 a.m. to 8 p.m. EST.

Confused?

TheStreet.com

explains how the rules change when the sun goes down in Investing Basics: Night Owl, a section devoted to after-hours trading.