Let's be clear, this is a way to try, not indefinitely use different versions of Windows 7 from one DVD or .ISO image. A small tweak will allow users tech-savvy enough to get a taste of all the versions of Windows 7.
Now, why do you need a little technical expertise? You need to remove a file from the DVD or from the .ISO image. As Windows Secrets notes, all you have to do is delete the ei.cfg file.
To make things easier for you, the ei.cfg file is in the sources subdirectory (WS didn't indicate its location).
It's simple enough: if you have an .ISO file use an appropriate .ISO imaging program to delete the file from it, then save the image and burn it. If you have the DVD you can use the same program to rip the DVD to an .ISO image, then delete the file, and reburn it.
