When it comes to third-party retail stores, Apple is more selective than the PC manufacturers about where it will sell its products. The California company's flagship retail outlet is the Apple Store, which first opened its doors in 2001 at the Tysons Corner Mall in McLean, Va. Since then, Apple has opened more than 300 additional stores in 43 states and 11 countries [source: [source: Apple]. Because these outlets are generally built only in large population centers, Apple has entered into several on-again off-again agreements with electronics chains like Best Buy, CompUSA, Computer City, Fry's Electronics, Micro Center, Office Max and Sears to reach a broader customer base. Still, Macs aren't available at many of the stores that sell PCs -- namely the world's largest retailer, Walmart. Of course, you can order Macs and Windows machines from stores on the Internet, as well.
Microsoft has a very different strategy. The company doesn't make hardware -- it licenses its Windows operating system to other companies. Most of those companies push their products into as many stores as they can. So while you might not see an Apple computer in your local computer shop, you'll see dozens of Windows PCs.