Did You Hear About the Morgans? Marc Lawrence, 105 mins, (PG)<br/>Spread, David Mackenzie, 96 mins, (18)<br/>Post Grad, Vicky Jenson, 90 mins, (12A)<br/>It Might Get Loud, David Guggenheim, 98 mins, (PG)

Hugh Grant has already starred in two romantic comedies written and directed by Marc Lawrence – Two Weeks Notice in 2002 and Music & Lyrics in 2007.

Both were honourable attempts to make a grown-up, literate rom-com, but neither of them gave Four Weddings a run for its money, so you'd think Grant and Lawrence might have shaken hands and gone their separate ways. But no, they've reunited for Did You Hear About the Morgans?, and it's business as usual – another well-meaning comedy, with all due care paid to the dialogue, but hardly a case of third time lucky.

If Grant had an inkling during filming that this was a collaboration too far, his discomfort is there in his performance, which is so stiff and posh he could be auditioning for a Prince Charles biopic. His leading lady is Sarah Jessica Parker, who plays ... well, Carrie Bradshaw. She may be an estate agent rather than a columnist, but she's the same tough-skinned but soft-centred Manhattan shopaholic that Sex & the City fans worship, and everyone else wishes would go away.

She and Grant play a married couple – the Morgans, of course – who broke up after Grant slept with a colleague. Three months later they meet for dinner to discuss their future, but the evening comes to an abrupt end when they witness a mob execution. They're whisked away by the FBI for their own safety, and deposited in a Wyoming cowboy town where there are more horses than Democrats. Worse still, they're forced to live under the same roof (under the supervision of the local lawman and woman, Sam Elliott and Mary Steenburgen). Even if you're fortunate enough to have missed New in Town or The Proposal, two rom-coms that transplanted city slickers to the back of beyond last year, you can guess what happens. The Morgans are shocked to be where they can't buy a pair of $1,000 shoes, but they soon grow fond of it, and – who knows – maybe even each other.

Lawrence is aiming at a "comedy of remarriage" of the kind that Grant's namesake Cary once made, but the laughs in those came from all the abuse that the hero and heroine poured over each other before they realised that no one else could ever insult them with the same passion. Grant and Parker, on the other hand, are so boringly civil that there must have been a marriage guidance counsellor standing just out of shot. And if there's scant friction between the Morgans themselves, there's even less between the Morgans and their new surroundings. At first, they're a bit spooked by how quiet the countryside is, but they get along quite well with everybody, and they don't develop any strong feelings, positive or negative, about the town or its people.

Certainly, nothing happens that prompts them to reassess their careers or their relationship. They're not fish out of water; they just fish in slightly different water. I won't reveal if they get back together at the climax of the film, but for Grant and Lawrence it's definitely time for a decree absolute.

David Mackenzie, the director of Hallam Foe and Young Adam, introduces us to another of his trademark ladykilling drifters in his new film, Spread. Ashton Kutcher, who's also the producer, plays a feline Hollywood gigolo who lives a life of carefree luxury by moving in with wealthy older women, Anne Heche among them, even though he has no house, job or car of his own. As Kutcher's coolly self-congratulatory voice-over sets out his methodical seduction techniques, the film begins as an astute, sardonic indictment of Californian self-indulgence. But as there's nothing to the central character except his supremely selfish lifestyle, when that's taken from him by the inevitable romance and redemption, it's hard to care what happens.

In Post Grad, Alexis Bledel leaves college and assumes she'll sail into "a sweet job at the finest publishing house in LA", if there is such a thing. But instead she finds herself unemployed and living back home with her parents. It's not a bad topic for a comedy, especially in the current economic climate, but the film-makers don't have the faintest idea what to do with it. Bledel hangs around, biding her time until she falls in love with her emasculated, servile best friend, while most of the script comprises the painfully pointless antics of her zany family.

The race for the Most Stupid Film of 2010 starts here.

The new documentary from the director of An Inconvenient Truth, It Might Get Loud assembles Jimmy Page, The Edge and Jack White to bond over their love of the electric guitar. But once they're in the same room, the men don't have much to say, and the film immediately splits into three distinct profiles of the musicians.

Each one contains some excellent material, but there's no disguising the inconvenient truth that It Might Get Loud is actually three short documentaries that have been chopped up and shuffled together for no apparent reason.