Did you know you can run Windows programs without owing or running Microsoft Windows? Linux and FreeBSD users have been doing this for years using WINE. As well as others with ReactOS-- a windows compatible operating system based on the Microsoft's APIso. ReactOS, while borrowing and contributing much to the WINE project is not Linux or any variant of Unix, it's designed to behave like Windows, similar to FreeDOS has done for MSDOS. Did I mention these are free?

WINE (Wine is Not an Emulator) for Linux/FreeBSD provides a compatibility layer so that Windows applications can be run like native Linux applications, and has been in in development since 1993. In theory, WINE will also work under Mac OS X, but Apple's X11 implementation is rather buggy, so it's not recommended (apple doesn't want you to use X11 apps, and they want developers to make native Aqua apps for the Mac and learn a whole new programming language called "Objective C").

So, what runs in WINE? Well... Left4Dead, all source and Unreal engine based games. All modern Valve games (Left4Dead, for instance, detects if you are running WINE and will behave appropriately), Fallout 3, all Windows warcraft games, Adobe any version of Adobe Photoshop, InDesin CS2, and some early versions of Illustrator will work under Wine. Adobe taps into some rather obscure aspects of the OS to make their software perform better which dramatically hurts it's compatibility with WINE and future Windows operating systems.

WineHQ keeps a database of applications that have been tested under WINE. You can find that list at: http://appdb.winehq.org/

If all you do is word processing, browsing the web, and play OpenGL games like Unreal Tournament 2004, any Source Engine games (Left4Dead, Team Fortress 2, etc) and just about all Valve games, Fallout 3, Warcraft III, and many others, Spore (when purchased from a store or from Steam, EA download manager does not work), and many DirectX 9 games, then there are several very good, and free, alternatives than to using Microsoft Windows.

For a complete windows compatible operating system, there is ReactOS, which borrows heavily from Wine (and also contributes to the Wine project), and, as such, offers the same compatibility (if not a little more) than Wine for running Windows applications. ReactOS is still in the Alpha stages. They are also a bit of a black sheep in the open source community because they are in the "I Hate Unix" category. By the way, if you're using Mac OS X, you're using Unix... a bastardized version of Free BSD, but it's Unix nonetheless. 3D Graphic studios lie Pixar and ILM often use Apple computers running Linux natively, and Mac OS X in a virtual machine on their desktop.

These windows-countability layers (WINE) and operating system (ReactOS), are malware-compatible. The good news is, under Linux, malware is much easier to get rid of. See Another report of malware running on Wine. Had this not been Linux running Wine, Windows XP would have needed to be reinstalled due to the malware's overwriting of critical system files. To be fully compatible with Microsoft operating systems, these inherent security flaws have to remain intact. The good news is, Malware running under WINE can't infect anything except for files installed in the WINE folder, not the rest of the Linux system.