With release of OS X 10.8.3, the latest update for Mountain Lion, Apple upgraded the Boot Camp utility, which allows users to dual-boot Windows and OS X on a supported Mac, to version 5. Boot Camp 5 allows users to install either 64-bit editions of Windows 7 or 8 alongside their copy of OS X -- by downloading Boot Camp Support Software 5, you’ll have all the drivers you need to run Windows on your Mac.
One consequence of upgrading to Boot Camp 5 is that support for 32-bit versions of Windows – including XP and Vista as well as 32-bit iterations of Windows 7 and 8 – is no longer supported.
Boot Camp 5 effectively ties Mountain Lion users into choosing Windows 7 or 8 as their alternative OS by dropping support for all previous versions of Windows. It doesn’t affect existing Boot Camp installations, so should you wish to install XP, Vista or a 32-bit version of Windows 7, make sure you set it up now before applying the OS X 10.8.3 update. Alternatively, go down the virtualization route by installing a copy in a virtual machine for free using VirtualBox.