How does the Windows 7 DVD know if it started the PC?
The DVD does not read the environment for that, since I already tried that route by editting its environment (batch files) to reflect that of the system boot disc. That failed.
So, the DVD must be writing to and reading from the system boot disk as it boots and as it is about to run an install procedure.
The question is which files and/or folders are involved, along with which registry settings has it written to, and subsequently reads from, if any?
The result I want is to be able to boot the Windows 7 DVD and do an in-place (version to version) upgrade (now referred to as repair installation).
Microsoft's insistence that such a repair installation take place only from the desktop, pretty much leaves out anyone that cannot get to the desktop to repair it. Duh.
Think outside Microsoft's box and the answer is there somewhere. Try a mantra other than Microsoft's... :-)