Microsoft probably thought it had a free shot next week.

It was a logical idea. After all, no matter what the product ecosystem--whether it's operating systems or movies--other competitors have a habit of clearing out the way of a major, dreadnought-style release. Ever notice how nobody ever attempts to open a film on the same weekend as, say, the newest Batman or Transformers flick? Same principle here: Windows 7 was going to launch on Oct. 22, and Microsoft's competitors would lie low until after the initial hype had passed to make their countermoves.

Steve Jobs and his merry little elves didn't get that memo.

For the third quarter of 2009, Apple shipped about 1.6 million Macs, and its market share (according to Gartner) stands at 8.8 percent. That's robust, and in keeping with a more generalized growth in PC shipments for the same quarter. When Apple reports its financial results on Oct. 19, chances are good that its growth numbers will be strong.

That data, apparently, has imbued Apple with the vigor to try and seize a little mind share from Microsoft as the latter rolls out Windows 7. According to BusinessWeek, Apple plans on launching a series of ads that play on the alleged difficulties of upgrading from Windows XP to the new Microsoft operating system. Apple's evident hope is that a few people, spurred by the Windows 7 hoopla into heading for the mall to upgrade their aged hardware, will give Macs a look instead of going straight to the PC section.

I'm not convinced it will work.

First, let's take the people heading out on Oct. 22 or the weeks afterward to purchase Windows 7 for their relatively new systems. The combination of an anemic economic climate (Everyone who thinks we're out of the recessionary woods, raise your hands. Yep, I thought so) and personal belt-tightening makes it unlikely that someone heading out for a $119.99 Microsoft Windows 7 Home Premium Upgrade will spontaneously decide to drop a card for the $1,499 MacBook Air.

A similar principle, I suspect, will govern the majority of buyers out there, even those looking to upgrade their antiquated desktops and laptops for something shiny and new. Apple hasn't announced any price cuts or new models--although rumors are rumbling--and the average Mac's price is still two or three times that of a new Windows 7-loaded PC. The combination of Microsoft's massive ad campaign, cheaper PCs and the uncertain economy will basically give Microsoft what it wants, sales-wise, at least in the short term.

But that doesn't mean that Apple can't do what it does best: pester Microsoft until Redmond regards it as a much larger competitive threat than Apple's market share at least currently suggests. A new ad campaign from Cupertino could also contribute to Apple's longer-term goal to incrementally gain market share.

There could be another rationale for Apple's ad campaign, of course. The reviews of Windows 7 have generally been positive, and Jobs could fear that the new operating system will eliminate the reasons--security, ease of use, aesthetics--that led so many users over the past few years to jump the PC ship for a MacBook. In that case, the ads become a sort of preemptive attack, the opening bell of what Apple may regard as a title fight.

Either way, though, barring an unexpected announcement from Apple (or Google), Microsoft will most likely have much of the next month to itself, competitively speaking.