* Nasdaq halts trading because of technical issues
* Hewlett-Packard weighs on Dow after revenue comments
* Indexes up: Dow 0.2 pct, S&P 0.6 pct, Nasdaq 0.9 pct
NEW YORK, Aug 22 (Reuters) - Trading was halted on the Nasdaq stock exchange on Thursday because of technical problems while U.S. stocks rose slightly.
All traffic through Nasdaq stopped at 12:14 p.m. (1614 GMT), the exchange said on its website, adding that trading in all Nasdaq-listed shares would be halted until further notice.
The Securities and Exchange Commission said it was monitoring the situation, while Nasdaq, owned by NASDAQ OMX Group, urged securities firms to route all their trades elsewhere.
"We're in the moment of unknown right now. We see bumps (in trading) often, but they're usual brief and rarely this broad based," said Frank Davis, director of sales and trading at LEK Securities in New York. "We're trying to figure out when things will get cleaned up."
The Dow Jones industrial average was up 31.38 points, or 0.21 percent, at 14,928.93. The Standard & Poor's 500 Index was up 9.10 points, or 0.55 percent, at 1,651.90. The Nasdaq Composite Index was up 31.38 points, or 0.87 percent, at 3,631.17.
Trading on the New York Stock Exchange continued, with major indexes higher. The Dow industrials rose for the first time in seven sessions after upbeat data from the world's top economies more than offset lingering uncertainty over the Federal Reserve's stimulus program.
Gains in the Dow were limited by Hewlett-Packard, which dropped 11 percent to $22.39 a day after reporting a decline in Enterprise Group revenue, the company's second-largest division and a critical component of Chief Executive Meg Whitman's plan to transform the company.