One-joke movies are usually little more than a TV skit stretched out to nearly two hours. In the case of "Weekend at Bernie's," however, it's one sick joke stretched out to nearly two hours.

The joke is that two bozos have to make a dead body seem alive by dragging him around and moving his head and legs and arms so others won't know that he's kicked the bucket.

To make that work you first have to have the dead person be so despicable that his death isn't a sad occasion. Second, the two protagonists have to seem forced into this action so they don't become seamy themselves. Third, the film itself has to be howlingly funny so the audience doesn't have time to think about it.

"Weekend at Bernie's" manages well enough on the first count, though the second and third are only sporadically successful. Overall what we have here is a black farce that has some very funny scenes but probably not enough to warrant your parting with $5.50.

Variations on this theme in the past have been attempted by Bette Midler in "Jinxed," Blake Edwards for "S.O.B." and even Alfred Hitchcock for "The Trouble with Harry," all to varying degrees of success.

"Weekend at Bernie's" stars Andrew McCarthy and Jonathan Silverman, two young actors you may recognize if you've seen such films as "Mannequin" or "Brighton Beach Memoirs," respectively.

The story has McCarthy as the slimy climber and Silverman as the shy workaholic, two buddies who work together in a major Manhattan business. The opening scenes in New York City are quite funny, playing off general stereotypical perceptions.

But the laughs become more sporadic as McCarthy and Silverman discover someone has been embezzling funds, information they take to their boss Bernie (Terry Kiser), not realizing he's the embezzler. Bernie promptly invites them to his beachside mansion in the Hamptons and then goes to mobsters he is apparently in cahoots with, asking them to kill McCarthy and Silverman. Instead, they decide to kill Bernie for his sloppiness and because he's having an affair with the wife of the mobster kingpin.

When the boys show up at the beach, their host is dead. But they are determined to keep him alive, at least for appearances' sake, fearing they will be targeted for murder if they don't.

The result is a series of set-pieces — some funny, some not — as they put sunglasses on him and manipulate his hands and arms with string, tie their shoelaces around his legs to make him appear to be walking, grab the back of his head to make him nod, accidentally take him water-skiing, etc. The sickest joke is when the dead body is reclining in his bed and his drunken girlfriend enters the room, has a sexual encounter and then comes out again, singing and still unaware that her Bernie is dead.

Despite that scene, which warrants an R rating in my mind, the movie is rated PG-13 for violence, profanity, vulgarity, drug use and lots of skimpy bikinis.

Of the two stars' characters, Silverman's is the least well-defined. He's supposed to be shy and endearing, yet he seems more manipulative and at times a pathological liar as he woos an intern (Catherine Mary Stewart) from his office.

But it's clear that acting honors must go to Terry Kiser as Bernie the body. At times he seems more lively than anyone playing a living character in this film. A dubious distinction, but he accomplishes it well.

That, unfortunately, is more than can be said for the film as a whole.