You do have Java 6 on your system? LW 5 requires Java 6 installed.

I'd suggest uninstalling the version you have, then download & install this version http://www9.limewire.com/download/LimeWireWin-full.exe. Uninstall the other version via Start menu > All Programs > LW > Uninstall.

Before you install it, delete your LW preferences folder, found here: Point #2 & 3 in Fixes for Limewire (sample image included at bottom of page.)

or for vista http://www.gnutellaforums.com/genera...der-vista.html