Windows 7 Home Premium and Professional same media?
If I have media for Windows 7 Professional and a license key for Home Premium, can I use my Professional media and my Home Premium key to install Home Premium or do I need to wait until I can get Home Premium media?
Solution 1:
If you look at this article, there are ways to install any version from the media. It just requires changing one file and thus copying the media. So, the immediate answer is that you can't do what you want but with a little work you can.
I suspect the reason for this change comes from the way product keys are handled. With Vista you had to enter the product key before installing Windows. With Win7, you don't have to enter the product key up front. If users were allowed to choose what to install, they might choose ultimate and then find out 30 days later that their key is only for Home Premium.
Solution 2:
Technically, the media contains all editions on it and you can use tools such as WAIK to create an unattend script to install other editions however out of the box, each DVD can only install the edition that it was intended for.
Solution 3:
There are unofficial releases of media that can install any version of Windows 7 (32- and 64-bits, Starter through Ultimate) called All-in-One (AIO). These were created using the Windows Automated Installation Kit for Windows 7 and usually still require a valid license key (ie: they aren't pirated, pre-activated installations).
However, using official media, that isn't possible.