January 16, 2012, 8:58 PM — Despite the Mac's recent gains in market share, Windows is still the dominant operating system, especially in businesses. That means there may be times when you need to run the Microsoft OS: perhaps there's an application your company uses that's only available for Windows, or you're a web developer and you need to test your sites in a true native Windows web browser. Or maybe you want to play computer games that aren't available for OS X. Whatever your reason for running Windows, there are a number of ways your Mac can do it for you.
If you need just a single Windows app, you may be able to do so using CrossOver ( Macworld rated 3 out of 5 mice ), which can run such applications without requiring you to actually install Windows.
If you need a more flexible, full-fledged Windows installation, you still have several other options. You could use Apple's own Boot Camp, which lets you install Windows on a separate partition of your hard drive. Or you could install one of three third-party virtualization programs: Parallels Desktop 7 ( Macworld rated 4 out of 5 mice ), VMware Fusion ( Macworld rated 4 out of 5 mice ), or VirtualBox ( Macworld rated 3 out of 5 mice ), each of which lets you run Windows (or another operating system) as if it were just another OS X application.
Of those four options, Boot Camp offers the best performance; your Mac is wholly given over to running Windows. But you have to reboot your system to use Boot Camp, so you can't use it at the same time as OS X; it's Mac or Windows, but not both. And while VirtualBox is free, setting it up is complicated—downright geeky, at times—and it lacks some bells and whistles you might want. Which leaves Parallels Desktop and VMware Fusion as your best alternatives.