The Nasdaq fell 65.26 to close at 3,205.35, and the Standard & Poor's 500 index dropped 17.53 to 1,381.52.
The Dow fell 211.43 to 10,323.92, led by Microsoft.
At the close of regular trading, Intel was down $2.19 at $115.19. Microsoft dropped $4.06 to $61.50. A final decision on the remedy phase of the software giant's antitrust case could come as early as next week.
The initial public offering of Centillium Communications, a broadband technology company, was the largest percentage gainer on the Nasdaq Stock Market. Its shares rose $6.13, or 27 percent, to $29. The offering was priced at $19 and opened at $23.31.
The CNET tech index lost 35.88 to 2,448.12, dragged down by shares of CMGI and American Power Conversion. Losers edged out winners, with 69 of the 99 stocks in the index falling, 29 rising and one remaining unchanged.
Of the 18 sectors tracked by the index, PC software companies posted the sharpest drop, falling about 5 percent. Wireless companies were the day's largest gainers, climbing 3 percent.
CMGI fell $6.06, or 12 percent, to $45.44, while American Power slid $3.81, or 12 percent, to $29.13. DoubleClick dropped $5.38, or 11 percent, to $45.56.
Ciena gained a day after Deutsche Banc Alex Brown started coverage of the stock with a "buy" rating. The shares rose $6.81 to $104.50. E*Trade gained $1.19 to $15.13 despite being cut to a "hold" rating at ING Barrings
The Philadelphia semiconductor index fell 13.49 to 901.71, led by chip designer Rambus, which lost $14.63 to $153.75.
Shares of Global Crossing dipped $1.38 to $24.94. Managers and others connected to the company, whose stock has fallen by nearly half this year, sold 8.39 million of its shares valued as much as $278 million.