I'll take a stab at this: yes, you can import your old private key. Provided you have it on disk somewhere. Did you think to save it? Or know where GPG4WIN (apparently what you were using) would store it?The GPG application generally stores it in the user's home directory under a ".gnupg" folder. Since GPG4WIN is a port of GPG for Windows, I assume it would leave fundamental things like that alone and put it in your C:\Users\<username>\.gnupg directory. It should be labeled "secring.gpg". That's your secret keychain. Don't give it out or anything. Just import it.Your public keys (including imported ones) should be in the same location in the file "pubring.gpg". I don't think your private key should show up in your key manager. But when you say "key manager," I don't even know what you're talking about, frankly. I tend to avoid all the high-level simplifications that Ubuntu and "friendly" Linux distros like it provide, so that's about all the help I'm going to be (whether it's of help or not, lol). I've learned more about computers struggling to use Linux than I ever learned in really any other way. It hasn't always been fun though...Anyway, remember: a public key is used to encrypt for the corresponding private key. You probably don't want your SECRET KEY showing up in your PUBLIC KEY ring, right? I mean unless you add your own public key to it or something.Good luck.