* New-home sales well short of expectations
* Microsoft climbs after announcing CEO Ballmer's retirement
* Indexes up: Dow 0.03 pct, S&P off 0.12 pct, Nasdaq up 0.27 pct
By Chuck Mikolajczak
NEW YORK, Aug 23 (Reuters) - U.S. stocks inched higher on Friday as trading resumed without interruption a day after the Nasdaq stock exchange suffered an unprecedented, three-hour trading halt.
Microsoft rose 5.9 percent, giving the Nasdaq composite index its biggest lift, after Microsoft Chief Executive Steve Ballmer announced he will retire.
After a technological problem shut down trading in Nasdaq securities on Thursday, Chief Executive Officer Robert Greifeld said the Nasdaq resolved the technical issues that led to Thursday's trading halt but cannot guarantee there would be no future problems.
Ballmer will retire within the next 12 months, once Microsoft chooses a successor. The stock traded at $34.31 a share.
Even with the Nasdaq outage on Thursday, the S&P 500 managed to register its biggest percentage gain since Aug. 1, but was unable to close above its 50-day moving average for a fifth straight session. The mark, now at 1,659.34, has become a technical hurdle.
"We've got the 50-day (average) right there. We are all kind of still catching our breath after yesterday's flash freeze," said Ryan Detrick, senior technical strategist at Schaeffer's Investment Research in Cincinnati, Ohio.
"The Microsoft news got everybody a little excited and caused some volume in tech, but that is only the main headline news today."
The benchmark index is on pace for a slight gain for the week after two consecutive declines, as investors exercise caution amid uncertainty over how soon the Fed will begin to wind down its $85 billion a month stimulus program.
The next Fed monetary policy meeting is scheduled for Sept. 17-18.
Economic data showed sales of new single-family homes in America fell by 13.4 percent in July to an annual rate of 394,000 units, well below expectations of 490,000 units.
The data weighed on homebuilder stocks, with PulteGroup down 1.8 percent to $16.02 and Toll Brothers off 2.6 percent to $31.61. The PHLX housing sector index lost 1.7 percent.
The Dow Jones industrial average rose 4.42 points or 0.03 percent, to 14,968.16, the S&P 500 gained 1.95 points or 0.12 percent, to 1,658.91 and the Nasdaq Composite added 9.867 points or 0.27 percent, to 3,648.575.
Pandora Media Inc slumped 12.3 percent to $19.04 after the Internet radio service said late Thursday that rising expenditures to acquire music and expand its sales force would push fiscal 2014 earnings below analyst expectations.
Aeropostale Inc tumbled 20.4 percent to $8.74 after the teen apparel retailer forecast a deep third quarter loss.