The Dow and S&P 500 stock indexes opened flat on Friday as data showed the labor market deteriorating further while the unemployment rate hit its highest since 1983, underscoring the severity of the recession.

Research in Motion , which posted surprisingly strong results and gave a rosy outlook after Thursday's close was the top boost to the Nasdaq. The BlackBerry maker's U.S.-listed stock surged 21 percent to $59.40.

Data showed U.S. employers shed 663,000 jobs last month, pushing the unemployment rate to 8.5 percent, while January's data was revised to show 741,000 jobs lost, the biggest decline since October 1949.

The Dow Jones industrial average <.DJI> gained 3.59 points, or 0.04 percent, to 7,981.67. The Standard & Poor's 500 Index <.SPX> gained 0.73 points, or 0.09 percent, to 835.11. The Nasdaq Composite Index <.IXIC> gained 2.58 points, or 0.16 percent, to 1,605.21.

(Editing by James Dalgleish; Editing by James Dalgleish)