* S&P 500 posts worst weekly percentage loss since November
* Google and Microsoft earnings help boost wider market
* Boston in virtual lockdown as police hunt bomb suspect
* Dow up 0.1 pct, S&P up 0.9 pct, Nasdaq up 1.3 pct
U.S. stocks rose on Friday as earnings from Google and other companies lifted tech shares, but the gains weren't enough to stop the S&P 500 from suffering its worst week since November.
High volatility marked the week, with the S&P 500 falling 2.3 percent on Monday in its worst day since Nov. 7, which fueled talk that the market's long-awaited pullback had arrived.
Friday's trading volume, at 6.4 billion, was the lowest of the week, but in line with the average for the year. Much of Boston, a major U.S. financial center and home to a number of the country's biggest mutual fund companies, was under virtual lockdown as police killed one suspect in the Boston Marathon bombing in a shootout and mounted house-to-house searches for a second man.
For the week, the S&P 500 ended down 2.1 percent. The index, however, managed a finish above its 50-day moving average after ending below the level on Thursday for the first time this year.
Boosting the S&P 500 on Friday were shares of Google, which gained 4.4 percent to $799.87 a day after posting upbeat results.
The Dow finished barely in positive territory, held back by shares of International Business Machines, which posted their largest drop in eight years after the company's quarterly results missed estimates. IBM's stock ended down 8.3 percent at $190.
"Unless there's a shock to the system, investors will move back into the market as we head through earnings season, but now investors have an opportunity to study the winners and losers more closely," said Michael Sheldon, chief market strategist at RDM Financial in Westport, Connecticut.
The Dow Jones industrial average rose 10.37 points, or 0.07 percent, to 14,547.51 at the close. The Standard & Poor's 500 Index gained 13.64 points, or 0.88 percent, to finish at 1,555.25. The Nasdaq Composite Index rose 39.69 points, or 1.25 percent, to close at 3,206.06.
For the week, the Dow slid 2.1 percent, while the Nasdaq lost 2.7 percent. Markets were roiled earlier in the week by the plunge in gold prices and slower growth out of China, the world's second-largest economy.
Still, the S&P 500 remains up about 9 percent for the year, and analysts said the pullback could give investors a chance to reevaluate their bets.
Less-than-stellar earnings from McDonald's and General Electric also weighed on the blue chips.
Options volume began the day unusually light for expiration day, which is typically a heavily traded session. But trading in options picked up as the day progressed and ended in line with average levels.
On last month's expiration day, overall volume spiked to 8.6 billion shares traded, the busiest day of the year so far, but expiry days in January and February had volume of just 6.7 billion to 6.8 billion shares.
Friday's volume was roughly 6.4 billion shares traded on the New York Stock Exchange, the Nasdaq and the NYSE MKT, in line with the average daily closing volume of about 6.4 billion this year.
Advancers outnumbered decliners on the New York Stock Exchange by a ratio of about 11 to 4, while on the Nasdaq, nearly 17 stocks rose for every eight that fell.