Download and install the gpg for windows at https://gpg4win.org/download.html
1. Open the GNU Privacy Assistant
2. Click the Keys menu > click Import Keys
3. Browse your GPG secret keys stored from your USB. Example of filename: secret-key-123456C3.asc
This file contains both the Public & Private key
4. Once it successfully imported then click Windows menu > File Manager
From File Manager, browse your encrypted file e.g. password.zip.gpg then a password dialog box will appear.
You will enter the password of your gpg. That’s it!
More info at https://www.gnupg.org