Which installer have you been using? The online installation can be a pain.

Try this:
First, update your Java. Use the JRE offline installer & remove your current Java version before you install the new one. See point 1 below
Fixes for LimeWire

Next, delete LW's preference folder when LW's properly closed (check in Task Manager). That's points 2 & 3 above.

Last of all, reinstall LW using the offline installer here
http://www.limewire.com/english/content/download.shtml

See if that fixes things