Three things I could think of.....
Delete the LW preference folder.
Read here on how to delete this folder (Point #2 & 3 in Fixes for Limewire)
http://www.gnutellaforums.com/showth...threadid=36420
Second:
Changing the compatibility mode:
Maybe changing the compatibility mode might also have an effect. Right click the exe icon, go Properties>Compatibility and change it to Windows NT (or Windows 2000)
Use crlt&alt + delete one time to open the task manager. Then go to Processes and see whether there is a limwire.exe running. Force it to end.
Uninstall all Java versions on your system. Reboot and then download the JRE offline installer of the newest Java version from here:
http://java.sun.com/j2se/1.5.0/download.jsp
Install it and reboot again, then reinstall LW.