How to Select Windows 7 Version on Install

Here's a quick tip for making sure you can select which version of Windows 7 you want to install on a system. This is especially useful if you have multiple keys for different OS versions (Home Premium, Professional, etc.)

If you look in the /sources/ folder (either in the .iso or on the media), look for a file ei.cfg. If this file does not exist, the Windows setup will allow the user to select the OS version to install. If the file exists, it will specify which version the installer will use by default. The file will look like:

[EditionID]
Ultimate
[Channel]
Retail
[VL]
0

From here, you can either edit the file to use your desired version by default, or simply remove the file to give yourself the option later. Doing either of these is quite simple if the iso had already been copied to a bootable USB. Otherwise, you will need to use an .iso editing tool to make the change. Good luck!

Source