When you do reinstall Java & LW, make sure to use the offline installers. For Java, use the JRE offline installer & remove your current Java version before you install the new one
http://java.sun.com/javase/downloads/index_jdk5.jsp
Before you reinstall LW, delete LW's preferences folder. See point 3 below. If you've used much older versions of LW in the past, there might be a prefs folder in point 2's location as well...check both.
Fixes for LimeWire
Also try changing compatibility (point 5 above).