1. Try deleting your LW Preferences folder whilst LW is
closed; instructions here:
Point #2 & 3 in Fixes for Limewire (sample image included at bottom of page.)
2. If that doesn't do the trick, remove your java using the Add/remove programs control panel. Then, reinstall Java but only using the "Offline" installer which is about 18 MB in size;
Java 1.5 (take the JRE)