正式なコメント

Yes; copy this folder:
C:\Users\<youroldusername>\AppData\Roaming\Pioneer
Note that the AppData folder is hidden, so enable hidden files in the Windows file explorer.
Put it in the same place on the new computer and if the username is the same, no changes are necessary, otherwise you'll need to dig in and find the rekordbox3.settings file, open it with a text editor and change the path to any of your files within to match the new username.
Also, as the path to the music would likely be different, you may need to batch-relocate - follow the instructions here.