HDCP and Vista...

Windows Vista is going to support HDCP natively, HDCP as I wrote earlier is going to be the next generation of encryption which, encrypts the signal between drive and Graphic card (in a PC) and between graphic card and the screen. This is supposed to stop piracy once and for all, it also forces the consumer to upgrade their PC's Vista and HDCP standards. Vista is fairly power hungry it needs to run: a modern processor (at least 800MHz),512 MB of system memory, a graphics processor that is DirectX 9 capable.
And that is just the minimum recommended is the following:
1 GHz 32-bit (x86) or 64-bit (x64) processor,
1 GB of system memory,support for DirectX 9 graphics with a WDDM driver,
128 MB of graphics memory (minimum), Pixel Shader 2.0 and 32 bits per pixel,
40 GB of hard drive capacity with 15 GB free space,
DVD-ROM Drive,
Audio output capability,
Internet access capability.
WDDM is a standard that is included in newer graphic card drivers, so basically you have satisfy those specs plus of course the HDCP compatibility, which is a High-end Graphic card Geforce 7900 or higher, a screen that can read HDCP and of course the drive that can read Blu-Ray or HD-DVD.
Yes, this new upgrade is quite a handful and will force many people to upgrade or replace their computer systems.

Vista specs (Microsoft)