Mark Rasch at SecurityFocus is concerned about the end user licence that will come with Microsoft's Vista operating system. Recommended reading.
"The terms of the Vista EULA, like the current EULA related to the “Windows Genuine Advantage,” allows Microsoft to unilaterally decide that you have breached the terms of the agreement, and they can essentially disable the software, and possibly deny you access to critical files on your computer without benefit of proof, hearing, testimony or judicial intervention. In fact, if Microsoft is wrong, and your software is, in fact, properly licensed, you probably will be forced to buy a license to another copy of the operating system from Microsoft just to be able to get access to your files, and then you can sue Microsoft for the original license fee. Even then, you wont be able to get any damages from Microsoft, and may not even be able to get the cost of the first license back...
Now Microsoft will invariably deny that what they are doing is “self-help.” More likely, they will claim that the disabling provisions of the software are mere “features” of the software. They will also argue that the licensee controls whether or not the code disables by either registering, or “getting Genuine.” But what the boys in Redmond are really doing is deciding that you have not followed the terms of a contract (the EULA) and punishing you unless and until you can prove that you have complied.
And what if Microsoft is wrong, and they disable your software erroneously? Well, you can keep buying and activating their software until you are successful. And that means more fees to Redmond. Or, following the movie “Happy Feet,” you can decide to find software with a little penguin on it."