Question: Is it possible to find out what version of Windows 7 I have installed (for example Home Premium 64-bit) by looking at the files on the disk?

The disk I have is a MBR installed Windows 7 copied to a GPT formatted disk, and the bootloader is kind of out of order, so I can’t verify.

Also, for whatever reason I have not been able to open the registry on the disk, so a method that does not need it is preferred.

Is the version string stored in any file?

Answer: Look in the %SystemRoot%. There should be an .xml file with the name of the installed edition (eg. HomePremium.xml). For the architecture, the easiest is to check for the presence of the SysWOW64 folder.