NEW YORK – Wall Street capped one of its worst weeks ever with a wild session Friday that saw the Dow Jones industrials rocket within a 1,000 point range before closing with a relatively mild loss and the Nasdaq composite index actually end with a modest advance. Investors were still agonizing over frozen credit markets, but seven days of massive losses made many stocks tempting for traders looking for bargains.

The Dow lost 128 points, giving the blue chips an eight-day loss of just under 2,400, or 22.1 percent. The average had its worst week on record in both point and percentage terms. The Standard & Poor’s 500 index, the indicator most watched by market professionals, had its worst weekly run since 1933.

The latest loss also means the Dow is down more than 40 percent since reaching a record high close of 14,164.53 a year ago, on Oct. 9, 2007. The S&P 500, which reached its high of 1,565.15 the same day, is down 42.5 percent.

Investors suffered a paper loss for the day of about $100 billion, as measured by the Dow Jones Wilshire 5000 index. For the week, investors lost $2.4 trillion, and over the past year, the losses have piled up to $8.4 trillion.

But there were signs Friday that some investors might believe the market was at or near a bottom. Just one day earlier, selling accelerated in the last hour of trading, giving the Dow a loss of 678 as many market players fled, while Friday, many people were clearly buying. And the Russell 2000 index, which tracks the movements of smaller company stocks, had a 4.66 percent gain Friday; small-cap stocks are often first on investors’ shopping lists when they think a market turnaround is at hand.

“Nobody wants to miss the bottom,” said Anton Schutz, president of Mendon Capital Advisors in Rochester, N.Y., who said of the Dow’s performance, “I view it as a victory that we only finished down 100.”

Some investors may have been placing bets ahead of the weekend meeting of officials from the Group of Seven nations, who gathered in Washington, D.C., to discuss the economic meltdown. One of the potential remedies expected to be reviewed at the meeting is for governments to guarantee lending among banks.

“Everyone is hoping for really good news that can invigorate some buying and break this credit freeze, but your guess is as good as mine as to whether that will happen. I think people are desperate for action,” said Jon Biele, head of capital markets at Cowen & Co. “It truly is remarkable to watch what’s happening.”

Still, Friday’s widely mixed finish was proof that Wall Street remains deeply troubled, and trading was likely to remain volatile when the market reopens on Monday.

“This kind of volatility in the market tells you that there are huge disagreements among investors about what the fundamentals are, about what the outlook is,” said Ethan Harris, managing director and chief U.S. economist at Barclays PLC.

The hair-trigger mentality of the market – a reflection of the anxiety on the Street – was evident from the opening bell. The Dow fell 696 points in the first 15 minutes, recovered to a gain of more than 100 before that first hour was over and then turned sharply lower again. It spent much of the session with a deficit between 300 points and 500 points, regaining some ground and then falling again – until the last hour, when the average had swings spanning hundreds of points that took the Dow up as much as 322.

Investors have shuddered the past month over a credit market that remains frozen, posing a threat to the economy. But Friday’s gainers included financial stocks, the ones most decimated amid the ongoing banking and credit crisis.

Harris said policymakers likely will continue taking steps to revive the credit markets, whose problems have caused Wall Street’s huge decline. Actions taken so far by central banks, among them the Federal Reserve, have included increased lending and interest rate cuts.

“The deeper problem is not the stock market drop but the freezing up of the credit markets, and that’s the root problem and they have to keep applying the antifreeze until it works,” Harris said.

The Dow fell 128.00, or 1.49 percent, to 8,451.49. It crossed the line between gains and losses 32 times during the session.

The Dow rebounded from a low of 7,882.51 for the day – the worst trading level since March 17, 2003. Still, its close was the lowest since April 25, 2003.