Can I Install Windows 7 Home Premium From A Profesional Disc Can I Downgrade From Windows 7 To Vista Home Premium Using An Upgrade Home Premium Disk?

Can I downgrade from windows 7 to Vista home premium using an upgrade home premium disk? - can i install windows 7 home premium from a profesional disc

I'll buy a new hard drive on my laptop and I'll clean installation of Windows 7 on the subject. I wonder if I have to use a disc of Vista Home Premium upgrade, or you need a clean install of Vista by the fact that Microsoft do as a decline.