There is a software diagnostic tool on CyberLink website that checks if your PC or notebook is HD DVD or Blu-ray compatible. The tool is free and in its beta version. You can download from here: http://www.cyberlink.com/english/support/bdhd_support/diagnosis.jsp
I think the most important component in a PC for BD and HD-DVD playback is an HDCP-enabled video card. Without HDCP hardware in place even the most powerful CPU and GPU will not play HD-DVD or BluRay movies. ADDED: MS announces full HD playback ONLY on 64-bit Vista: http://www.apcstart.com/site/dwarne...other-feature-full-hd-playback-in-32bit-vista