The problem is that the older one was given the letter c: and the newer one is e:
I didn't want the older one to be c:, since it's going to be mainly for backup files, so Dad changed it to z:. But when he tried to change e: to c: it wouldn't let him, because it's the system drive.
So I shrugged and said no big deal. But now some of my software won't install because I don't have a valid c: drive, even though I told it to install on e:
I'm guessing I'll have other problems from the same thing down the road. How do I fix this? Do I need to reinstall Windows, and if so, how? And how do I prevent the same thing from happening again?