Why cant I upgrade my windows vista to windows 7 anymore?

So a couple years ago I bought a student upgrade for vista ultimate to windows 7 professional. They allowed me to install from email but they also sent me a back up disc too. The install then went smoothly and I had absolutely no problems upgrading from vista ultimate to professional 7 and kept all my files too. So I just bought a SSD for my computer and wanted to install my OS on it and I installed Vista Ultimate perfectly on it while formatting my old HDD too. Then when I put in my windows 7 disc it wont let me upgrade at all. It says I cannot upgrade windows vista to windows 7 professional. What the hell? It worked before. So it told me to do a full custom install and I did and windows 7 installed just fine but then it asked me for a product key and alas the upgrade disc didn't come with any product key at all so I can't activate it at all. I tried to check to see if maybe the product key was in the original email but I can no longer access my student email anymore as I'm not in college anymore. So I currently have windows vista installed again and made sure it was verified before trying to upgrade and still no luck. Just trying to figure out what's going on. Do I need to buy windows 7 all over again? Do I need to be connected to the internet for this to work because vista isn't picking up my wireless card right now? or will updating my vista service package help rectify the problem? Any help will be appreciated. So stressed right now.

@blazinpuertoroc:

Call MS and they'll help you get a product code from Vista.

My academic Windows 7 Pro (along with Office 2013 Enterprise) was free in my university. It has a CD key for one license which was located on my email invoice.

Did you check yours?

To avoid a potential problem like yours, I made a hard drive image backup (using Windows Backup). Went without a hitch when I upgraded to a bigger hard drive.

http://www.pagestart.com/win7bckuprstrnhd072610.html

Incidentally, I still have active email accounts on the last three colleges and universities even though I moved on (and an alumni on one of them).

@jun_aka_pekto: Yeah, I can no longer access my email unfortunately. But I cannot for the life of me access the internet on windows vista but it worked fine when I was on 7. Good god Vista is the scum of OS's everywhere.

I think I have a backup somewhere. Maybe that might actually work but I don't think I have enough space on my SSD for it to work.

update: i think I may be able to restore my windows 7 to my old HDD, get rid of all of the extra space I need and clone everything over. Wish me luck.