I just attempted to install version 7600.16385 x64. It remained an attempt as the install simply "hung" and couldn't continue after a reset. I haven't had this problem with any previous versions of NT 6.1, including RC 7100 (and later). Apparently something has changed in this version making it hardware-incompatible with the machine I was installing on (HP mh9452, less than a year old). Has anyone else encountered this ? IIRC there were a lot compatibility problems with older hardware when NT 6.0 was released but I can install that without problems on hardware that pre-dates that release by 4 years.