Consumers who purchased a Windows 7 PC on June 2 or later – up until January 31, 2013 – can now register for the Windows Upgrade Offer announced in May, which will give them the option to purchase an upgrade to Windows 8 Pro for only $14.99. Those eligible for the promotion will receive a promo code via email after the operating system is generally available on October 26.

Over at the Windows Upgrade Offer website users will need to provide Microsoft with details including name, email address, phone number, the date of purchase, the retailer, the PC brand and model, and in some cases, the 25-character Windows 7 product key associated with the PC.

You will have until February 28, 2013 to register for the offer to get Windows 8 Pro for $14.99. The code will be redeemable through Microsoft's Windows 8 Upgrade Assistant, bringing down the regular $39.99 upgrade price for Windows XP, Vista, and Windows 7 systems purchased prior to June 2.

The $40 upgrade price for older systems is only good if you purchase it online – it will be sold for $69.99 at retail stores. The company hasn't yet announced the price of a full retail version of Windows 8, but The Verge says it has received an insider tip claiming it will be priced at $199 after a promotional price of $69.99 expires on January 31, 2013. Apparently, a Windows 8 to Windows 8 Pro upgrade option will also be sold at retail stores for $69.99 until January 31, when the price reverts to $99.99.

The lower prices are designed to drive adoption of the new OS early on. If the reports are accurate, once the promotional period is over, Windows 8 will actually be priced similar to its predecessor at launch.

The latest report contradicts a previous rumor suggesting Microsoft would ditch the full retail version of Windows 8 in favor of the presumably cheaper OEM option for home users building a PC, in addition to their upgrade offers for users of a previous version of the operating system.