The software giant pledged in May that anyone who bought a Windows 7 PC after June 2 would be able to upgrade to Windows 8 Pro for $14.99. The registration is to be open until January 31, 2013. If people miss the registration period, they'll have to pay full price for the software.
Windows 8 is drastically different than earlier iterations of Windows. It's Microsoft's answer to the question of how to integrate mobile and desktop computing and includes features like touch screen ability, fewer icons, and the capability to unify all devices.