The Nasdaq composite index fell 23.93 points to 2,034.83 for the day after closing up for three days this week. The Dow Jones industrial average shed 110.84 points to 10,604.59.
JDS Uniphase was the Nasdaq's second most actively traded stock, making significant gains after an upgrade from Wit SoundView. Shares rose 85 cents to $11.76.
Shares of Symantec and its rivals were rattled Friday after the security and antivirus software maker warned that its first-quarter earnings will fall well short of Wall Street estimates. Symantec fell $22.41 to $38.90.
Other antivirus and security companies affected were Network Associates, which tumbled $1.97 to $10.60, and Internet Security Systems, which fell 7 cents to $46.67.
Manugistics Group fell $10.97 to $25.40 despite reporting a first-quarter profit that met analyst expectations. Analysts downgraded the shares citing concern over smaller-than-expected license revenue.
Micron Technology rose despite the company's disappointing third-quarter report. After the market close Thursday, the memory chipmaker said memory prices plunged in the third quarter and took the company's earnings down with them. Shares were up 67 cents to $38.38.
Semiconductor stocks overall were having a strong day; CNET's Semiconductor index rose 3 percent.
Among other technology bellwethers, Microsoft fell $1.07 to $68.83, Intel rose 34 cents to $27.61, Cisco Systems rose 16 cents to $17.52, and Oracle dropped 42 cents to $17.48.
Staff and Reuters contributed to this roundup.