Before You BuyEstablish Your Needs

Can't decide between a Mac and a PC? Luckily, you don't have to: You can install and run Windows - and any Windows programs - on a Mac. All it takes is some tinkering and a little extra dough.

You've got a couple of options when you want to run both OSes: You can choose whether your Mac runs OS X or Windows as you start up your computer, or you can run both OSes simultaneously and switch between them on the fly. Your decision will most likely rest on convenience and how often you need to switch. (For the Windows part of this setup, you can use either Vista or Windows' earlier incarnation, XP.)

The Either/Or Option

OS X includes a program called Boot Camp Assistant that helps you install Windows on a Mac. When you run Boot Camp (Finder -> Applications -> Utilities -> Boot Camp Assistant), it first checks to see how many hard drives you have. If you have a single drive, Boot Camp partitions it, meaning that it sets aside some space for Windows so that OS X lives on one part of your drive, and Windows lives on the other (see photo). If you have two or more drives, Boot Camp asks you where you want to install Windows. You can choose to dedicate an entire drive to Windows and its applications, or you can set aside just a portion of a drive, just as you would in a one - drive installation.

Boot Camp sets up a Windows partition on your Mac's hard drive.

Boot Camp then reserves the drive space and prompts you to insert your Windows installation CD and to click Start Installation. It then turns the Windows set-up process over to Microsoft's installer, and you follow Microsoft's instructions to complete the set-up. After a mandatory system re-start, your Mac powers up in Windows (by default, Macs load the most recently installed operating system on start-up). Boot Camp has you insert your OS X CD, which automatically detects the Windows OS and installs drivers that let Windows talk to your system. Now you're ready to run either OS.

You choose which operating system to run in a couple of ways. To change your default OS, go to Apple -> System Preferences and click Startup Disk. You'll see icons for both OS X and Windows; select the one you want to load on start-up and close the Startup Disk window. The next time you power on your Mac, it loads the OS you chose.

If you want to change operating systems after you've powered up your Mac, follow the instructions above but click Restart in the Startup Disk window instead of closing the window.

Finally, to start your Mac in an operating system other than the default for just a single session, hold down the Option key as you power up and select the OS you want to load from the list that pops up.

While Boot Camp is free with your Mac, you have to buy Windows separately, and that'll cost you $120 to $230, depending on which version you get (XP or Vista Home Basic, Home Premium, Business, or Ultimate) and where you buy it.

Virtual Windows

VMWare Fusion runs Windows applications inside a window on your Mac.

If you don't want to restart your Mac each time you need to switch operating systems, or if you need to switch between OS X and Windows frequently, you may find it more convenient to run both OSes simultaneously. Boot Camp Assistant can't help you here - you need to buy a program that sets up a virtual version of Windows on your machine.

This mode is called "virtual" because Windows runs as an application under OS X, rather than as an operating system on its own. You launch Windows the same way you'd launch any other application, such as a Web browser or email program: you double-click on the Windows icon. Windows will run in a separate window on your desktop, just like any other program (see photo). It gets your printer to print and your modem to connect solely by talking to OS X, which in turn tells the printer and modem what to do.

Two programs, Parallels Desktop and VMWare Fusion, help you set up Windows under OS X. They cost about $80 each, and, or course, you'll need a copy of Windows, too.