A legal copy of Windows is expensive, but what do you get? Windows and Office are licensed, not sold.
By using these products, we have to agree to a number of harsh restrictions. For most Windows licenses, you can't keep the software when you change the hardware. You sometimes can't even give your software away. Who can run the software? On which computer? What can you do with it? The list of restrictions is long and some items are outrageous.
No source code
The source codes of Windows and Office are hidden, so, no one is allowed to understand how these programs work.
If you can't get a right to inspect source code (the human-readable inner workings of a program), you can't have someone correct flaws or evaluate how your privacy is protected for you.
And guess what? On software that comes with source code, viruses and spyware aren't effective, and security isn't bought on extra. The antivirus software industry, in which Microsoft is now a significant player, prefers you to use Windows.
What about choice?
Software should come without locks in it.
Why are Office documents difficult to export? Why are the formats continually changing? Why can you not even uninstall some programs? It might be that if you look for choice, Microsoft products aren't for you.
Stand for a free society
A free society requires free software. Think of "free" as in freedom, not price: the freedoms to inspect, learn from, modify the software you use.
Computers are used to share ideas, culture and information. Without these freedoms over software, we risk losing control over what we share.
This is happening today. From plain annoying technologies such as Digital Restrictions Management (DRM) to downright frightening ones like Trusted Computing, everyone's ability to participate in culture is threatened.
If you have to give up your freedoms to use software, maybe you should not be happy with it.