Although registration opened today, orders will not be fulfilled until Windows 8's on-sale date of Oct. 26, Microsoft reminded customers. "Starting on October 26, we will start sending out promo codes via email with purchase instructions," said company spokesman Brandon LeBlanc on a Microsoft blog.

The code will change the upgrade's price to the discounted $14.99; Microsoft will serve upgrades as a download that installs the new OS.

Customers who qualify for the $14.99 deal must provide Microsoft with 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 may be required to enter this as part of the registration," said LeBlanc.

The key requirement may be part of Microsoft's anti-piracy strategy. When Computerworld tested the upgrade registration process, first posing as a U.S. customer, Microsoft did not ask for a key and approved the registration. A second test, however, posing as an Indian consumer, asked for a key. "We can only validate your registration when you submit a qualifying Windows 7 product key," the registration site stated during the second test.

According to the Business Software Alliance, India's 2011 piracy rate of 63 percent was more than triple the 19 percent in the U.S.

It's unclear how Microsoft will prevent scams of the system -- attempts to qualify for the cheaper upgrade by providing bogus information -- if the process does not require a product key in every instance. Making enforcement even more difficult are Microsoft's terms, which let a customer who is legitimately eligible for the $14.99 price to apply the upgrade not only on the recently purchased PC, but on "any compatible Windows-based PC with a qualifying operating system."

Computerworld's tests, including the one that was quickly approved, were conducted on a Mac, even though the upgrade offer FAQ clearly states, "This upgrade offer requires you to use your Windows PC to register."

Closer to the Oct. 26 ship date for Windows 8, registered users will receive an email that includes the promo code, download links and instructions, and information on how to buy the optional $69.99 installation DVD.

Microsoft has expanded the deal from 131 markets to a total of 140. The company has posted a list of eligible countries, upgrade languages, and accepted currencies on its website.

Each customer may apply for up to five discounted upgrades, assuming he or she purchased that many new PCs from June 2 onward.

The promo codes must be redeemed, the $14.99 payment made and the download completed no later than Feb. 29, 2013.

The second Windows 8 upgrade offer -- a $39.99 upgrade to Windows 8 Pro for owners of older Windows XP and Vista PCs, and Windows 7 machines ineligible for the less-expensive upgrade -- has not yet begun taking registration information. Like the $14.99 upgrade program, the more inclusive deal will let customers download the upgrade starting Oct. 26.

This confirmation email is sent after completing the order for the $14.99 offer; a second email will arrive later with the promo code for the discounted upgrade.