Updated from 4:08 p.m. EDT

Stocks shot higher on Monday, as life -- and trading volume -- returned to normal on Wall Street following a massive power failure in the Northeast last week. With little in the way of economic data, stocks soared on a combination of strong retail sales and big moves in semiconductor names.

The

Dow Jones Industrial Average

gained 90.76 points, or 1%, to 9412.45, while the

Nasdaq

added 37.48 points, or 2.2%, to 1739.49. The

S&P 500

rose 9.07 points, or 0.9%, to 999.74.

While the upswing shows investors remain bullish about the economic outlook for the second half, some market watchers were mystified by the strength of the move, which helped the Dow close past 9400 for the first time since June 20, 2002.

The move came on small volume, however. The

New York Stock Exchange

traded 1.13 billion shares, while the Nasdaq Stock Market traded 1.47 billion shares. On Friday, the NYSE traded 455 million shares for the entire session, while the Nasdaq traded 597 million.

"I was a little surprised. The decent news about

Wal-Mart

(WMT) - Get Report

saying sales were above expectations for the week helped. And it looks like tech stocks, especially

Yahoo!

(YHOO)

,

Amazon

(AMZN) - Get Report

and

eBay

(EBAY) - Get Report

, are up a lot," said Giri Cherukuri, head trader at OakBrook Investments.

"That's what's going up, but I'm not sure the reasoning behind it. In the broader picture, people are looking at the economy doing well in the second half and that creates some optimism. Improved sentiment is a good story for a flat day, but not necessarily an up day like this."

Indeed, retail strength appears to have continued in the month of August, driven by back-to-school sales, with Wal-Mart announcing sales would reach the high end of its forecast, which calls for growth between 3% and 5%. In July, Wal-Mart made a similar statement and sales easily beat estimates. Shares rose 82 cents, or 1.4%, to $58.92.

Tech was also strong, with the aforementioned Amazon, eBay and Yahoo! all up more than 4.7% on the session. Elsewhere, in the semiconductor sector,

Advanced Micro Devices

(AMD) - Get Report

gained $1.11, or 14.2%, to $8.91 after a

Barron's

story said the maker of computer chips could raise its market share to 30%.

LSI Logic

(LSI) - Get Report

was upgraded to in-line from underperform by Smith Barney, sending shares up 68 cents, or 7.1%, to $10.27. All told, the Philly chipmakers were up 5.2% -- hitting a 52-week-high in the process.

Big energy and energy-related names were also on the move, with

General Electric

(GE) - Get Report

up $1.02, or 3.5%, to $29.80, and

FirstEnergy

(FE) - Get Report

, currently under investigation as the potential source of the blackout, off $2.86, or 9.3%, to $27.75.

All in all, the Dow Jones Utilities Average was relatively unmoved by the blackout, standing slightly above where it was before the power grid failed. On Monday, the utilities were down 0.5%.

Alternative energy sources attracted investor interest -- and then faltered late in the session -- after a

Wall Street Journal

article highlighted

Capstone Turbine

(CPST) - Get Report

and

Plug Power

TheStreet Recommends

(PLUG) - Get Report

. Capstone rose 7 cents, or 4%, to $1.81, while Plug Power dipped 16 cents, or 3.1%, to $5.

Elsewhere in the space,

FuelCell

(FCEL) - Get Report

was down 25 cents, or 2.7%, to $9.15, while

Ballard Power

(BLDP) - Get Report

was up 52 cents, or 4.1%, at $13.37 after introducing a new power generator.

Elsewhere, hardware retailer

Lowe's

(LOW) - Get Report

announced second-quarter earnings of 75 cents a share, topping analysts' estimates by 6 cents, while guiding third-quarter earnings in line with expectations. Shares of Lowe's rose $3.06, or 6.3%, to $51.96, while shares of rival

Home Depot

(HD) - Get Report

, set to release earnings on Tuesday, rose 36 cents, or 1.1%, to $33.90.

Toys R Us

(TOY)

reported second-quarter losses of 2 cents a share, excluding items, on a revenue increase of 3.3% over last year's quarter. Going forward the company confirmed the 2004 guidance it gave in mid-May. Shares rose 83 cents, or 7%, to $12.71.

Kohl's

(KSS) - Get Report

shares dropped $1.09, or 1.7%, to $62.45 after Sanford Bernstein cut the company to market perform from outperform, citing valuation concerns.

AnnTaylor

(ANN)

shares gained 31 cents, or 0.9%, to $33.90 after UBS Warburg upgraded the company to buy from neutral, citing an improved second-half outlook for the ladies' apparel chain.

Broadcom

shares gained $1.59, or 7.5%, to $22.85 after Piper Jaffray analyst Ashok Kumar speculated on the chipmaker's future as a standalone company and raised the issue of a buyout in the years to come by rival

Intel

(INTC) - Get Report

in his morning note. Intel rose $1.14, or 4.6%, to $26.19.

Corning

(GLW) - Get Report

shares rose 15 cents, or 1.9%, to $8.14 after the company was started at buy at Fulcrum Global Partners. Computer maker

Hewlett-Packard

(HPQ) - Get Report

was up 73 cents, or 3.4%, to $22.13 a day ahead of releasing earnings.

Altria

(MO) - Get Report

, parent of cigarette maker Philip Morris, saw its shares fall 87 cents, or 2.2%, to $38.98. On Friday, Madison County Circuit Court Judge Nicholas Byron ordered Philip Morris USA to post a $12 billion bond or face enforcement of the $10.1 billion judgment from an earlier trial, in which the company was found to have misled smokers about the dangers of "light" cigarettes.

Elsewhere,

Abbott Laboratories

(ABT) - Get Report

and

Millennium Pharmaceuticals

(MLNM)

said they're ending a joint venture to develop and market diabetes and obesity drugs. Abbott will keep the license to develop the treatments. Shares in Abbott gained 11 cents, or 0.3%, to $39.79, while Millennium rose 44 cents, or 3.5%, to $12.97.

AOL Time Warner

(AOL)

shares were up 16 cents, or 1%, to $15.61 after its "Freddy vs. Jason" horror movie, produced by the company's New Line Cinema unit, debuted as the weekend winner at the box office, grossing more than $36 million.

On Friday, stocks rose slightly on thin trading volume. The Dow Jones Industrial Average closed up 11 points, or 0.1%, at 9321, while the Nasdaq finished higher by almost 2 points, or 0.1%, at 1702. The S&P 500 rose marginally to 990.

Overseas markets were higher. London's FTSE 100 ended its session up 25 points, or 0.6%, at 4272, and Germany's Xetra DAX closed up 63 points, or 1.8%, to 3507. In Asia, Japan's Nikkei closed up 169 points, or 1.7%, at 10,032, while Hong Kong's Hang Seng rose 100 points, or 1%, to 10,525.

Treasuries were slightly higher, with the yield on the 10-year note up at 4.49%. Crude oil prices for future delivery rose in London. The dollar strengthened against the yen and the euro.