I've got a Windows 7 Ultimate upgrade CD and a full Vista license (both are legit). I was under the impression that I could use the Windows 7 upgrade CD to do a full install and use only the activation code from the Vista CD. I partitioned my iMac with BootCamp and then choose a custom installation, formatted the bootcamp partition, and installed it. The install finished without a problem and then the computer rebooted to a blue screen. Do I need to install Vista first and then upgrade that to 7 or is the blue screen unrelated? Thanks!