I have a copy of Home Premium on the way for my Dell as its free upgrade. But Dell by all reports take an awful long time after release dates to send out these disks, so rather than put Vista on my new laptop, I've installed Home Premium from a download, the idea being to do an upgrade to the dell copy when it arrives, hopefully before the 28 days elapses. All works very well, but I notice in regedit that the buildex string is as above , with 'AMD64' replacing the x86/x64. The machine has a CoreDuo 2.4GHz. Do I have a hacked version please, or is this valid since I haven't come across it anywhere?