NEW YORK — After "Heroes" unexpectedly turned into one of its few successes this year, NBC said this week that it was betting on new fall series about a bionic woman, a time-traveling newspaper reporter and a computer geek with spy secrets embedded in his brain.

The struggling network also will try to stretch "Heroes" by spinning off a related six-episode "Heroes: Origins" series that lets the audience choose a new cast member.

Fourth-place NBC was the first of the broadcast networks to unveil a new fall schedule to advertisers this week. After showing signs of life last fall, NBC recorded its least-watched week in prime time in at least 20 years last month — then went even lower the next week.

The high-profile failure "Studio 60 on the Sunset Strip" is gone after a year. "Crossing Jordan" is canceled, after leaving the fate of its lead character in limbo following a season-finale plane crash. Donald Trump has likely hired his last apprentice, too.

"Law & Order" will be back for its 18th season and "Medium" will return, but not until January, when they take over a Sunday time slot filled by football in the fall.

With only four new dramas set to bow in the fall, and a drama and comedy each scheduled for midseason, it's a conservative schedule for a network badly in need of hits.

"Loading up on (new) product is not necessarily a recipe for success," said Kevin Reilly, NBC entertainment president. "Particularly in this day and age, with a fragmented audience, you simply can't market them."

"Bionic Woman" will air Wednesday, ahead of a new drama, "Life," about a detective given a second chance after being wrongly jailed for a crime. "Journeyman," about the calendar-skipping reporter, gets the post-"Heroes" time slot on Mondays. The computer geek "Chuck" shows off on Wednesday.

"We like the high-concept hooks," Reilly said. "But this was by no means an effort to replicate what we have on 'Heroes.' "

NBC kept intact its Thursday night lineup of comedies and "ER." Although shows like "30 Rock" and "The Office" are critical favorites, they aren't popular, leaving the network faltering on a night it once dominated.

"ER" enters the last year of its deal. Reilly said he would meet with creator John Wells in October to determine whether the series has life beyond next season.

The "Heroes: Origins" series is a novel way for a network to address one of its chief unpleasant lessons this season: Viewers are impatient when their favorite serials disappear into reruns for a huge chunk of the year. Each episode will introduce a potential new character, and the most popular chosen by fans will join the "Heroes" cast full time.

Brooke Shields headlines "Lipstick Jungle," a one-hour series about three high-powered women friends, with a script from "Sex and the City" author Candace Bushnell. It will bow next January.

Illustrating the difficulties in introducing new comedies, NBC said it will have only one new sitcom next season — and it didn't even earn a spot on the fall schedule. "The IT Crowd" is about a group of people who work in technical services at a large corporation.

The successful game show "Deal or No Deal," often NBC's most popular program, will air on Monday and Wednesday nights. Another new game, "The Singing Bee," features contestants trying to remember the lyrics to popular songs.