For the past two-plus years, Microsoft has stood by while Apple's "I'm a Mac, I'm a PC" TV commercials treated Windows Vista like a punching bag.

But starting next week, Microsoft will fighting back with its own ad, starring funny-man Jerry Seinfeld. And not a moment too soon.

"Microsoft let Apple have the podium and dominate the communication space," said David Graves, an analyst with Forrester Research. "It's not how you would do things in politics, where it's tit for tat. So it was time for Microsoft to strike back."

The reported US$300-million "Windows, not Walls" campaign will kick off next Thursday, September 4, with the airing of the first Seinfeld commercial, the Wall Street Journal reported last week. No coincidence, the NFL season kicks off that night on NBC.

Little else is known, but it has been reported that French director Michel Gondry, the man behind Eternal Sunshine of the Spotless Mind, may have directed the commercial.

That didn't keep the blogosphere from weighing in. And the reaction wasn't positive, reported Brandweek .

"Microsoft doesn't like being 'cast as a stodgy oldster' by Apple's advertising and has turned to Jerry Seinfeld. Oh, so they want to be cast as late-middle-age almost stodgy oldster," one blog quoted by Brandweek said.

Advertising industry experts say that whether choosing Seinfeld, 54, is on- or off-target depends on Microsoft's ambitions.

"Who is Microsoft really trying to target? If it is the thirty- and fortysomething business community, I think he's a great choice," said Marc Ippolito, president of Burns Entertainment and Sports Marketing.

But if the goal "is to woo the college-age and younger crowd to convince them not to switch to a Mac or to switch back," said Ippolito, 38, isn't so sure. "If you're 20 years old now and the show ended [in 1998] when you were 10, that's going to seem a long time ago."

Though the sitcom is widely seen in reruns, Ippolito says the "college kids in our office talk about Gossip Girl or The Office , not Seinfeld."

Steve Hall, publisher of AdRants.com, is more blunt. "If you want to make Vista a cool operating system, give it some cool. I don't think Jerry Seinfeld does anything that's cool."