So I'm looking into putting Windows Vista onto my MBP. My university offers a free digital download of Windows Vista Ultimate (32-bit) that I'd like to use (rather than buying windows 7 outright, since I can also get a heavily discounted upgrade as well). Most of the BootCamp guides I've ready specifically state the need for an installation disc, and I haven't found any guides specific to my situation on the forum (sorry if they are there and I missed them). Is there anyway to use a digital download only? Would I need an external HD? Any advice would be great. I'm only moderately technically inclined, so feel free to spell things out explicitly for me. Thanks!