I will say from the start I am still very skeptical about the goals of the TCG(The IP body behind TCPA). I see it as overly intrusive, and potentially a way for many companies to vendor-lock their customers. An open market is a good market. With that said, Microsoft has something quite, well, Microsoft. They supported TCG from the start and have helped produce many of the guidelines and documentation to be followed for hardware manufacturers and software vendors. And yet, like that have done before (with things such as MS Service for Unix, CSS support in IE, et cetera), they will apparently not be applying those standards to Windows Vista, their next-gen operating system set to start replacing Windows XP late next year. A bit of background on trusted computing, it is a technology designed to make the chain all the way from the manufacturer to the vendor to the consumer be secure, in both hardware and software, to ensure that nothing bad or malicious has occurred with it. What happens when the largest software company in the world doesn't support the very standards for that complex chain they helped create? That's right, the 'support' implemented by Vista becomes the de-facto standard, and what was supposed to be a secure ideal becomes frustration. Microsoft has not yet released a statement regarding this, so it may all be bunk but I'm not a believer.
You can have the most secure hardware in the world - but if the software running on it doesn't follow suit, all that secure hardware doesn't matter.