Can I upgrade to Windows 7 from Vista?

Hello,

I own a MacBook Pro and would like to install Windows 7 using parallel. I am looking for the most affordable way to get Windows 7 onto my Mac. I am a student and cannot afford paying full price for Win7 OS. So my question is If I buy and Install Vista using parallel, can I then Install Windows 7 professional onto it using parallel? This is the cheapest route for me because Windows 7 pro (upgrade) is available to students for only $65. So I can technically get Win 7 for less than $100.

So is this possible to do this in Parallel?

Thanks