Soundpad stores a working copy of the current sound list every 5 minutes, and once on application exit at %Appdata%\Leppsoft, which is equal to C:\Users\Username\AppData\Roaming\Leppsoft.
Soundpad creates daily backups of the sound list on application start and stores them in the above-mentioned directory.
Select File ▶ Restore sound list from the menu. Then you can choose, which backup to restore.
After you've saved your sound list or loaded one, you will see the path and name of the list in the title of Soundpad. Whenever you change something in your list, you will see an asterisk in the title, which indicates, that there are unsaved changes.
When you are about to switch computers or re-install the operating system, and want to keep the sound files and sound list, then use the export option: File ▶ Export ▶ Sound files.
Soundpad will ask you to select a directory for the export. All sound files of the current sound list are copied to the target directory along with a new sound list file. Afterwards, you can copy that directory to your new computer and just load the exported sound list file in Soundpad.