Spit, what version of Java are you using? In LW help > about LW will show you the version. If you're using 1.6.0_01 then try reinstalling this older version.
Java SE Downloads - Previous Release - JDK 5
Use the JRE offline installer & remove your current version of Java before you install this version.

Some people have had connection issues due to a recent Windows update. Check out this thread & see what Mickjapa108 says about it. He tells you how to check if you have this uupdate.
LimeWire will not connect for me anymore

If you have this update (or even if you don't!) then you could try port forwarding. Have a look on this site, your version of router's not listed but some of the other Netgear DG834 instructions might suit your router
PortForward.com - Free Help Setting up Your Router or Firewall

If that doesn't help then delete LW's preferences folder when LW's properly closed. See point 3 below (also point 2 if you'ver used much older versions of LW in the past...there could be a folder in both locations).
Fixes for LimeWire
This will kill all of your settings within options, you'll have to go back through afterwards & reset things.