So I bought W7 from the student thinger. They're meant to send me a disc so that I can install it easily (I CBA to make my own from the download) but that's not arrived yet.

So I decided to install my PC-world copy. Yeah I bought 2, whatevs.

For some reason my CDKey from the downloaded version wouldn't work with the disc from PC world. They're the same version and both 64-bit. Anyone have any idea as to why this is?

I've installed it already using the CDkey that came with the CD, but that's besides the point. Just curious is all.

Are you sure they're both upgrade?

Perhaps the encryption thingy on the disc is older/different to the one in the download?

I installed mine by downloading it. You don't get an ISO, you get an .exe. It's piss easy.

Upgrade/Retail keys are different, so are the discs in terms of the keys that are valid

That's pretty annoying, it's the upgrade.

Oh well, I guess I should've read it properly when I bought it >.<

Just means i'm gonna have to install Vista, then 7 straight away (I like fresh installs after a nice healthy format)

No you don't have to install vista first

I did a clean install with the Win7 pro 64 bit disc without an OS on the machine perfectly fine (ultimate steal one)
Just had to convert the download into a bootable iso (one small download + one command line command) and installed fine