The Nasdaq fell 58.50 to 3,400.98 on low volume, and the Standard & Poor's 500 index dropped 1.85 to 1,420.60.
The ratio between the stocks that advanced and declined on the Nasdaq was about even as 157 stocks set new lows compared with the 44 that set new highs and the 613 companies that remained unchanged.
The Dow Jones industrial average fell 4.80 to close at 10,522.33 led by Hewlett-Packard and IBM.
At the end of regular trading, Intel closed down $1.06 at $124.69. Microsoft also dropped 81 cents to $62.56.
Microsoft responded to the government for the last time before a federal judge rules in the landmark antitrust trial, which could come as early as tomorrow. The decision sets the stage for a potentially drawn-out appeal.
The CNET tech index lost 53.70 to close at 2,574.83, dragged down by shares of Qualcomm. Losers edged out winners, with 68 of the 99 stocks in the index falling, 29 rising and two remaining unchanged.
Qualcom fell $10, or 13 percent, to $66.38 on a volume of 54.6 million shares making it the most actively traded stock on the Nasdaq. VoiceStream Wireless also fell $5.38 to $114.50.
An analyst said Qualcomm's wireless phone technology will not be used by China United Telecommunications in a new network until next year.
Of the 18 sectors tracked, e-tailers posted the sharpest drops, falling about 4 percent. Computer-assisted design and manufacturing companies were the day's largest gainers, climbing nearly 2 percent.
On the upside, Parametric technology rose $1.13, or about 12 percent, to $10.63 and Unisys rose $1.75 to $27.13.
The Philadelphia semiconductor index fell 11.87 to 998.43, led by chip designer Rambus, which fell $12 to $176.25.
An industry group said worldwide sales of semiconductors will rise 31 percent this year and will continue to rise for the next few years on brisk demand.
Lucent Technologies, the world's biggest maker of telecommunications equipment, said today it would buy fiber-optical networking equipment company Chromatis Networks for $4.5 billion in stock. Lucent fell 38 cents to $57.38.
In a move to boost its wireless strategy, popular handheld maker Palm acquired Anyday.com, a company that manages personal calendar services online, in a cash and stock deal valued at $80 million. Palm shares fell $1 to $23.
Financially troubled business software maker Baan agreed today to sell its operations to Invensys, a U.K. automation equipment maker, in a deal worth 762 million euros ($708 million). Baan fell $1.44, or 34 percent, to $2.75.