When it launches this fall, upgrading to Windows 8 Pro will cost just $39.99. This aggressive pricing isn't limited to recent Windows owners — it will be available for PC owners who are currently running Windows XP, Windows Vista, or Windows 7.

Downloadable from Windows.com after launch, you’ll also be able to add Windows Media Center for free from the “add features” option within Windows 8 Pro after you download the update.

Customers who are looking to purchase a new computer in the coming months can opt to take advantage of a slightly different upgrade offer which will allow them to get the same update for $14.99.

If you’d rather own a physical disc, a packaged DVD version of the upgrade to Windows 8 Pro will also be available for $69.99.

“We believe that your upgrade experience in Windows 8 will be a breeze by offering a faster experience, a single upgrade path, and compatibility from prior versions of Windows,” a Microsoft representative said in a blog post announcing the pricing.

This is an aggressive pricing model for Microsoft. Windows 7 upgrade pricing was $119 for the Home Premium version and $199 for Windows 7 Professional.

In fact, the last time we remember Microsoft offering a Windows version upgrade for under $50, it was during the launch of Windows Millenium Edition. (Fortunately, Windows 8 looks like it will be a much better release than Windows ME.)

Perhaps Microsoft is taking a page out of Apple's playbook. Apple switched up its OS upgrade model in 2009 with the release of OS X Snow Leopard — charging just $29 for the new OS. It kept the $30 price tag for OS X Lion last year and at WWDC, Apple announced that OS X Mountain Lion would be just $19.99 and available to Snow Leopard or Lion users.

The $39.99 upgrade price for Windows 8 will last until January 31, 2013. A separate product – with pricing that has not yet been announced – will be available for customers who are building their own computers, or who want to put Windows on a computer that does not currently run the OS for the first time.

What do you think about Windows 8 Pro’s pricing? Will you be upgrading? Let us know your thoughts in the comments.