Assuming that you still can start up LW, check whether there is more than one LW .exe running in the Task Manager>Proccesses tab (also look for more than one Java).
If so, close it/them.
Another thing you could try is to go back to an older version of Java, which you can get here (use always the JRE offline installer):
http://java.sun.com/products/archive/
Post back on how you got on with it.
