Windows recovery will fix some problems, but it's not going to fix a registry hack that changed the location of where the OS thinks everything is at, and it isn't. And even if it fixes SOME of it, it's NOT going to fix it all. It is not even worth the time or effort, in my opinion, to mess with it. Just do a clean install and be done with it. Yes, you are going to lose some stuff, but to be blunt, you should have thought of that (If it is a problem) long before you started modifying things in the registry if you didn't know exactly what you were doing.
Furthermore, if you don't know how to disconnect a drive or connect a drive, then it might be best if you either found some assistance from somebody who DOES have some knowledge in this area or took it to a repair shop and had them do it for you. It's not that it's difficult, it's that you seem unsure of yourself and THAT usually leads to bigger problems.
If you can figure out how to disconnect the secondary drive by unplugging it's SATA cable and then figure out how to create installation media using the Media creation tool as outlined in my guide, then you might stand a chance of getting Windows installed and if anybody here is likely to be able to talk you though this it's USAFRet, but I gotta be honest, it's not looking good right now given what you already did PLUS "how to I disconnect a drive".