You need to tell us what firewalls you're using, who your ISP is & the brand & model of your modem &/or router

Try this version of Java. Use the JRE offline installer & remove your current Java version before you install the new one.
Archive: Download Java 2 Platform Standard Edition (J2SE) 5.0 Update 11

You say that you're using LW 4.2.6...is that a typo? Do you mean 4.12.6? Just checking