This is for a customer; I fix PCs for a living. Assume the retail Windows 7 CD (see below) is never used or activated, a sealed box from Best Buy for example AND is the FULL install version, not the upgrade.
I know there is a way WITH VISTA to do this: The PC partially boots (registry is corrupt or some OS file is corrupt). There **IS** a way to (from a Retail MS Vista CD **of the SAME version of Vista**) to do the install SO THAT the old data folder and program files folder are kept in a name.old folder that is easy to find after the reinstall. And then the user data is not lost and you can copy it into the new Documents and Music and so on folders from the name.old\users\user-name\documents folder and so on. NOTE: I do not remember what name.old exactly is ie it is Windows.old or Vista.old or something like that .
If you do not know how to do this OR what I am talking about DO NOT REPLY TO THIS QUESTION. This is NOT about a SCRATCH REFORMAT INSTALL and is NOT about an upgrade install. The latter is for a working PC going to a later OS; as stated my PC only partially boots.
What I do not remember is if the Retail CD is a different AND BETTER version of Vista, will it work. I,E Non-booting PC is Vista Home Premium and Retail CD is VIsta Professional.However, I am 90% certain that it will work; there is some special option that must be chosen during the Vista install to say the CD is a different Vista version than the PC has.
My question is can I do the above (keep the user folder and the program files folder in a name.old folder) if the partially booting PC is Windows 7 Home Premium and the Retail CD is Windows 7 Professional.
THERE ARE TWO QUESTIONS HERE.
(1) Can I do AT ALL with Windows 7 what I am 100% certain I can do with Vista (ie. do the install in a way that "backs up" the user data and program files folder to name.old **IF** the Win 7 version on the PC and the version on the CD are both the same (ex. both Windows 7 Home Premium).
(2) If the answer to (1) is YES, then will it ALSO work if the version on the PC is Windows 7 Home Premium and the version on the Retail CD is Windows 7 Professional. (i.e CD has a higher version of Windows 7).
And if so what is the key step in the install instructions that must be changed to reflect that the CD is a later Windows 7 version. i.e Tell me what to click or select in one or two relevant steps of the install.
Note: The answer is NOT to remove the HD from the PC, connect it to a Sata to USB converter (making it an external USB HD) and then copy the user data to another external USB HD via a working PC in the middle. Then do a scratch install of Windows 7 Pro and then copy the user data back in from the external HD. I know I can do this but it takes longer and one must be careful to find ALL the user data to copy etc.
i.e. Please stick to the technical question exactly the way I have stated it.