My concern: If I completely re-install windows vista 64-bit via format, then apply a windows 7 home premium upgrade. Will it be corrupted due to two different operating systems being installed to complete the windows 7 package If I paid $199.00 for a full version and installed it then I am guaranteed to have clean uncorrupted files, not mixed vista and windows 7 files. Maybe my thinking is off, but isn't it safer to go full version just to avoid unknown or unforseen software conflicts that will occur later on due to having vista installed first. I'd like to save $$$ by choosing the $119.00 option, but again I am worried about corruption and future conflicts by going the upgrade route vs the full version route. Please offer more incite on how the upgrade works, because I think mixing vista first then windows 7 next is a disaster waiting to show future conflicts.