Export all the MP3s you want for playback to an external memory device. Drag and drop from your music folder under "My Documents" to your external device. If you have designed any playlists that you'd like to keep, those can usually be found in the folder holding your MP3 playback application. Drag and drop those onto your external device as well.
Clean your jukebox PC of any extraneous material. You will not need to run a special program. Simply delete everything you do not need off of the computer by putting it in the Recycling Bin. If the computer does not have an MP3 playback program, download one now and fully install it. Thoroughly clean the PC with the canned air to prevent any future dust damage.
Connect your external drive to your jukebox PC, and drag all the music and playlists into the "My Music" folder under "My Documents." Once it has fully transferred, go to the File menu in your MP3 playback software and select "Add Folder." It will automatically add your music and your playlists.
Connect your speakers to the computer by plugging them into the "line out" port in the back of the computer. This port is usually light green, and may be labeled with either a headphones icon or a speaker icon. Then play back your music to make sure both speakers are working properly.