Hello Tim, As you have got the Upgrade version of Windows 7 Home Premium, I would suggest you to install the Windows Vista first and then Windows 7 Upgrade. Please ensure that the Vista OEM version which came with the computer is 64-bit. Else the Windows 7 Home Premium Upgrade Edition 64-bit would not be successful.  Please refer to the link mentioned below to perform the Re-installation of the Operating System. [URL]#Issue4 The following link mentioned below would help you with the Windows 7 Upgrade. [URL]  Please write back with results.
I'm upgrading my 4 year old XPS420 (on which I currently have Vista home premium) with new RAM, hard drive and operating system (Windows 7 Home Premium Upgrade Edition 64-bit). As I'm using a new hard drive, would I be better reinstalling the old Vista home premium using the OEM disk I got with the computer and then upgrading to Windows 7, or should I try installing the Windows 7 upgrade version directly onto the new hard drive (perhaps having to do a double install)?
New hard drive and Windows7 Upgrade DVD