Monday and Tuesday will be critical days for the ABC television network. In Los Angeles, it will hype its fall prime-time lineup to critics, who may write that fourth-place ABC finally has the roster of shows to turn around its lagging fortunes -- or that the Walt Disney Co.'s network faces yet another year in the cellar.

The other networks will do the same next week, in an annual, pressure-packed several days, as television executives work the critics and needle each other. For networks such as ABC, which hasn't been in first place since the 1999-2000 season (and only twice during the past 20 years) it may not be a make-or-break week, but it comes close, thanks to all the dollars hanging in the balance.

In this past television season, for instance, ABC had to charge about $30,000 less per 30-second commercial than CBS and NBC, both of which earn much higher ratings, according to Nielsen Media Research. During a single 30-minute sitcom with 11 commercials, this difference amounts to $330,000. Over an entire prime-time season, with about 20 programs in a weekly lineup, it equates to hundreds of millions in ad revenue lost for one reason -- ABC has been unable to pick shows that viewers like better than those on other networks.

Although ABC accounts for only a thin slice of Disney's revenue, it remains a target of unhappy shareholders and is one reason that Disney stock trades at half the price it did in 2000. ABC's most recent No. 1 prime-time show was "Who Wants To be a Millionaire" during the 1999-2000 season. Before that, you have to go back 15 years to "Dynasty," the top-rated show during the 1984-85 season. (ABC hit No. 2 in the early '90s with "Rosanne" and "Home Improvement.")

In the past decade, "from an outsider's standpoint, it seemed [ABC] lacked a point of view, lacked purpose," said Brandon Stoddard, a part-time motion picture professor at the University of Southern California who ran the network for four years before Disney bought it in 1996. "If you don't know where you're going, it's hard to get there."

Disney chief executive Michael D. Eisner has said that fixing ABC is the company's top priority. He and Disney president Robert A. Iger, a former head of ABC, have been telling investors that the money-losing network will be profitable by 2005. In April, they fired ABC's leaders and tapped Anne M. Sweeney from Disney's cable channels to become president of Disney-ABC television, and Stephen McPherson, head of Disney's Touchstone Television, to run prime time.

ABC has lacked two crucial elements that its more successful rivals have: stability in top management and franchise dramas. Since 1995, ABC has had six heads of prime-time programming. At Fox, Gail Berman has headed primetime since 2000. Jeffrey A. Zucker has led NBC prime time, maintaining top-ranked shows such as "Friends," since late the same year. At CBS, the top-rated network, chief executive (and Viacom Inc. co-president) Leslie Moonves has picked the prime-time lineup since 1995.

Building-block franchise dramas have proved highly lucrative for NBC and CBS. NBC launched "Law & Order" in 1990, spinning off "Law & Order: Special Victims Unit" in 1999 and "Law & Order: Criminal Intent" in 2001, all of which deliver high ratings and an affluent audience that advertisers like. CBS has done the same with its "CSI" series. ABC's last successful dramas were "NYPD Blue," which began in 1993 and hasn't been in the top 10 since the 1995-96 season; and "The Practice," which began in 1997 and only this fall has produced a spinoff, "Boston Legal."

Thus weakened, ABC may be more vulnerable to larger forces acting against networks -- the rise of cable.

That explains why the stakes will be high next week for ABC's new leadership when ABC cranks up its latest prime-time effort.

But McPherson, the man whose job depends on the new programs, won't even be at the big show in Los Angeles. At least not in person. He'll beam in via satellite from Paris as he's finishing his honeymoon, a move that may turn out to be confident -- or cavalier. In a recent interview in New York, McPherson, 39, counseled patience about ABC's performance, betraying no signs of sweating investor pressure.

"We haven't even set our five-year plan yet," said McPherson, a former Wall Street portfolio manager. "We're going to do our best to turn around prime. If that leads to profitability or break-even, that's great. We'll know more in the coming months when Anne and I have a chance to look at the financials and make sure we've got the money we need to turn prime around."

It's a deep hole to climb out of. In 2003, the ABC network reported an increase of $196 million in revenue compared with 2002, but that followed a disastrous 2002, during which the network suffered an $881 million revenue drop from the year before.

How exactly the network will go from black-and-blue to into the black is unclear. The facile answer, of course, is: Put hit shows on the air. But a line of executives stretching back years has found the task to be a perplexing puzzle.

McPherson and Sweeney stepped in just as the next season's pilots were being finished. Right away, they changed the way ABC picked prime-time shows. In the past, pilots had been viewed by a limited number of executives -- Eisner, Iger and top ABC brass. This year, McPherson and Sweeney flung open the process for viewing the 26 pilots, filling 15 screening rooms in Burbank during the first two weeks of May with all manner of company employees and soliciting their feedback.

At the end, each of ABC's division heads handed McPherson a dream schedule -- which shows they'd like to see and which night they should air. In the end, McPherson said, he and Sweeney chose the lineup.

"Did Michael [Eisner] and Bob [Iger] weigh in?" McPherson said. "Absolutely. And we welcomed it." But in the end, he said, "You have to be a benevolent dictator and say, 'Here's what I want to go with.' "

At ABC, the dictators have had a boss ever since Disney bought the network: Eisner. At every network save perhaps CBS, programming executives feel the hand of their superiors on the prime-time lineup. But at ABC, Eisner and Iger are even more involved, said an executive with knowledge of ABC who requested anonymity for fear of reprisal. In the past, the two have read pilot scripts, picked which pilots will be made and selected which mini-series will air, the executive said.

Further, Eisner and Iger have lost confidence in some former ABC executives, leading the two to take more of a hand in ABC prime time, a role Iger would rather not have, the executive said.

Advertisers have expressed confidence in McPherson's plans for steady growth. For instance, ABC's fall schedule was assembled to try to pick winnable nights, McPherson said, not to put new shows up against rival powerhouses, such as "CSI" and "Law & Order."

"If you're fighting Mike Tyson," McPherson said, "you don't run into the ring and take a big swing at him."

McPherson spent the past four years heading Touchstone, which creates programming for sale to ABC and other networks. ABC is routinely criticized for being offered last season's reality hit, "The Apprentice," and passing on it, but many in the industry believe NBC always had the inside track on the show. However, no one disagrees on this: When McPherson was at Touchstone, the company created a procedural crime drama and offered it to corporate cousin ABC, which passed, scared off because it was penned by an unknown writer.

CBS, however, picked up the show, and the top-rated "CSI" franchise was born, spawning "CSI: Miami" and "CSI: New York," which will make its debut on CBS this fall. (ABC also passed on "The Cosby Show," which went on to be an eight-year hit for NBC, but NBC passed on ABC hit "Rosanne.")

When McPherson took the job in April, his first call was to "CSI" producer Jerry Bruckheimer. "I told him how much we [ABC] want to get back in business with him and then I asked for 'CSI' back," he said, laughing. "I said I just need one."

CBS's Moonves responded: "Unfortunately, in network television, you only get one chance to say yes or no. Fortunately, ABC said no and we said yes."

Moonves praised his new counterpart at ABC.

"He clearly knows how to develop hit shows, and it all starts with that," Moonves said. "He's opinionated in a good way. The worst thing you can be is wishy-washy."

McPherson said that when he was running Touchstone, it was sometimes hard to tell who was in charge at ABC. "As a studio guy, you weren't quite sure who you were selling to," he said. "Who was going to be at the end of the line on the creative side?"

Susan Lyne, who then was president of ABC, did not return calls for comment. Lyne's peers at the other networks considered her a creative programmer with good instincts who was sometimes hamstrung by having to share authority with ABC chairman Lloyd Braun. Both were fired in April.

McPherson and Sweeney are making other breaks with the ABC of the past. Since the demise of "Millionaire," ABC executives have said the network was only "one hit" away from turnaround.

When McPherson and Sweeney took over, however, they realized the damage was more extensive.

"We both believe it's never just one hit," Sweeney said in a recent interview. "It's about three or four shows. It's about building nights."

"Super Millionaire" is the latest prime-time version of "Who Wants to Be a Millionaire," ABC's most recent No. 1 prime-time show.