Hollywood seems to think remakes are easy ways to make money; just pick a familiar title and let nostalgia do the work for you. Actually, as remake-weary viewers know, such movies are hard to do right.

This week's box office, however, proves it can be done, given the continuing success of "Beauty and the Beast" and the estimated $40.5 million debut of "Power Rangers." Disney's live-action remake of the animated classic held on to the top spot in its second weekend, with an impressive $88.3 million. (Some pundits predict that tally could go up to $90 or $91 million by Monday, a crazy-good total for a second weekend.)

The weekend results also offer a cautionary tale of how not to do it, with "CHiPs" opening well below expectations in seventh place, with an estimated $7.6 million.

Why did digging up the past work so well for "Beauty" and "Power Rangers," and so poorly for "CHiPs"? Here are the reasons.

1. Audiences Love Some Nostalgia -- Unless You're 'CHiPs'

"Beauty" and "Power Rangers" both date back to the '90s, yet neither ever really went away.

From the show and about $6 billion worth of toys out there.

"CHiPs" (that's how they spelled it then) may have had a big pop culture footprint 40 years ago, but aside from whatever lingering fondness our culture still has for the NBC motorcycle cop action series, which ran from 1977 to 1983, but the show hasn't been seen much in reruns since then. So it's hard to imagine too many fans, new or old, yearning to see Ponch and Jon ride side by side down the Pacific Coast Highway once more.

2. Update What Fans Love

"Beauty" maintained fan loyalty by not changing much at all. It did add just enough novelty (It's live-action now! With IMAX-worthy spectacle! And some intriguing sorta-gay subtext!) to justify the new version's existence.

"Power Rangers" was a trickier adaptation. The original was fun and campy and colorful but also thoroughly juvenile. What could give the Lionsgate remake appeal to fans who are now grown-ups as well as teens who've never seen the old show? Make it into a young-adult sci-fi/fantasy movie (with a strong dose of Marvel). This YA-y approach worked very well for Lionsgate in the past, with the "Twilight" and "Hunger Games" franchises. The result seemed to hit the demographic sweet spot, with the movie drawing an audience that was 50 percent over age 25 and 30 percent under 18.

"CHiPs" underwent a more radical overhaul, with writer/director/star Dax Shepard playing up the comedy and giving the characters elaborate backstories. In other words, it's "CHiPs" in name and premise only; most of what original "CHiPs" fans may have loved about the old show is gone. Granted, this approach worked for the "21 Jump Street" movies, but at least those were well-written and acutely self-aware. And they also had one asset that "CHIPS" lacks --

3. Star Power

The "Jump Street" movies at least had proven box office draws in Jonah Hill and Channing Tatum. "CHIPS" stars Shepard and Michael Peña are not proven ticket-sellers, and they're both lacking in the charisma department; they're not even as charming as Estrada and Larry Wilcox were on the small screen. With all this stacked against the film, on top of audiences not caring about the TV show at all anymore, it's amazing (and crazy) that Warners pulled the trigger on it at all. Let alone thought it was a good idea to begin with.

"Beauty" and "Power Rangers" both get by without star power being much of an issue. Because the titles and brand are the draw. "Power Rangers" features "Hunger Games" alumna Elizabeth Banks in a well-tailored role as its diva villain, but no one's coming to see her; it's all about the quintet of heroes in the candy-colored costumes.

4. Buzz Means Everything

"Beauty" did just okay with critics (earning a 71 percent "Fresh" on Rotten Tomatoes) but wowed audiences, who gave it an "A" CinemaScore. "Power Rangers" did not wow critics (46 percent on RT), but audiences ate it up anyway and gave it an A CinemaScore, too. Both benefitted from strong word-of-mouth, which was not the case for "CHIPS." Neither critics nor audiences cared much for it, judging by the movie's 20 percent RT rating and B- CinemaScore.

5. Family-Friendly Ratings

It probably didn't help that "CHiPs" was rated R, indicating a raunchiness that would both repel fans of the squeaky-clean TV show and keep out younger viewers.

"Power Rangers" may be a lot more mature than its TV source, but it's still rated PG-13, the ideal rating to draw fans who want to see a movie with some grit but without keeping young ticketbuyers away. Even "Beauty" is rated PG, which is about as far as it can go to indicate grown-up content while still being a family movie.

6. Timing

March has been a huge month for summer-style blockbusters, but this weekend was especially crowded, with three new wide releases competing. "Beauty" certainly benefitted from having last weekend all to itself. Still, even with the movie doing just half the business of last weekend's record-smashing debut, "Beauty" was still impossible to compete with, doing about $28 million more than the three new wide releases combined.

The week's lone new movie that wasn't a remake, sci-fi/horror thriller "Life," should have been a bigger draw for women, both because of its horror premise and the casting of both Jake Gyllenhaal and Ryan Reynolds. Nonetheless, the film opened in fourth place, underperforming with an estimated $12.6 million. "Life" failed to draw women (its audience was just 45 percent female), maybe because they were all still lining up for "Beauty."

You'd think "Life" would have done well, thanks to its star power and decent reviews. But audiences didn't like it (it earned a dismal C+ at CinemaScore), suggesting that the movie would have done poorly even on a less competitive weekend.

It's this kind of disappointing result, for an original screenplay filmed with a star-studded cast on a modest budget ($58 million), that leads Hollywood to believe it's safer just to keep filming remakes.