When Windows 8 launches later this year you'll be able to upgrade to the pro version of Microsoft's newest desktop OS for just $40 for a limited time. The deal will apply to a broad base of current Windows users including those running Windows XP, Vista and Windows 7. Microsoft had a similar offer during the launch of Windows 7 but this one is cheaper than its predecessor. (Windows 7 upgrades ranged from $50-$100 at launch.)