All your songs will be fine, as long as the files are outside the Limewire Application folder or preference folder, which they should be. in Limewire Library you can highlight a few songs and click expllore to make sure

BUT it is always wise to have back up copies of anything you value.. on disk or an external hard drive.
Do not be tempted ever to delete files from the Limewire Library.
I advise you to get the Basic 4.12.6 before paying for pro ... just to make sure it is OK for you before you part with your money. You will find it very different