If you're referring to the Limewire library, it only contains files that you downloaded with Limewire.

If you mean you want to share the files that are in your WMP library, you need to locate the folder(s) that contain those files. The library itself doesn't actually contain the files. If you need to, search your computer for one of the files to determine its location.

Then, in LW, go to tools...options...sharing

Click 'add' and browse for the folder(s) that contain the files you want to share.

Hope this helps!