The Windows 8 launch is arguably the biggest product release in Microsoft history. To support it, the company is breaking out its checkbook.

Microsoft is reportedly spending between $1.5 billion and $1.8 billion on its Windows 8 marketing campaign, according to Forbes. That's significantly more than what the company reportedly spent on the Windows Phone 7 launch in 2010, the last huge shift for Microsoft.

When contacted by Wired, a Microsoft spokesperson said that the company does not comment on rumors and speculation.

Microsoft hasn't given us much sense of where the the billion dollars of advertising is going, or what its Windows 8 campaign will look like. Earlier this week, four alleged TV ads leaked, revealing that Microsoft might focus more on showing consumers Windows 8's various features, rather than attacking other platforms. And it seems that the ads are targeted both toward people who are familiar with the Windows desktop and new buyers.

Another product Microsoft is clearly funneling advertising dollars into is Surface. Simple, sparse ads for the device have already popped up in subway stations and at bus stops, while chalk drawings have appeared in some hip locales including the Mission district in San Francisco and Brooklyn, New York.

This fall will be huge for Microsoft, with not only the Windows 8 and Surface launches, but also with Windows Phone 8 soon after. Windows Phone 8 executives have publicly said that the company will make a huge marketing push in order to make consumers more aware of the platform. Microsoft will also likely spend a lot of money into training carrier retail salespeople to ensure that Windows Phone 8 is pitched to consumers. And it won't be alone. Nokia CEO Stephen Elop says that his company will also be investing a "disproportionate share" of its Windows Phone 8 Lumia launch money into retail training.

Microsoft is set to launch Windows 8 and Surface on Oct. 26. The company opened up pre-orders for the Windows 8 Pro upgrade package and many Windows 8 devices on Friday. The Windows Phone 8 launch is scheduled for Oct. 29.