Most programs record their location details with the registry, and can't be moved around after installation. The number of programs that let you move them is vastly outnumbered by those that won't work after you do. Steam is one of the few programs that will work for, i know it lets you save game folders between installs too.
You don't go into registry without knowing where you going first.
I mean, its probably technically possible to edit registry so it forgets some of the things you did but that level of wizardry is above me, and not for ordinary mortals to attempt (I am talking about myself BTW). If system restore doesn't work i would put everything you want to save of C drive onto that 1tb drive and do this (remembering to choose 'save files' or you will lose all your documents and stuff): It is your best hope to come out of this without needing to reset windows 10.
