Try removing all LW rules from within Norton & then add them from scratch.

After you deleted LW's preferences folder, did you have to go through the setup wizard again?

Have you been through the other fixes in this thread (click on link)?: If LW Will Not Connect

Go & find your gnutella.net file... how big is the file?

Please give us your details: System details - help us to help you -> Provide these details when you post!!!

OMG i tried the Gnutella.net method twice and it worked omfg ty birdy so much i could give u a massive hug mate !! look at all the info i had down to help you XD.

Though i wish every one good luck with their own problems.

. OS version? (eg: Windows 98): I have Windows vista and I do have an adminastrater account.
2. What firewalls you have?: I have Norton 360 and I beleive Windows Defender is a firewall aswell.
3. How much ram?: I beleive I have 1024 mb (sticker is fairly faded).
4. Hard Disk space available?: Around 55gb +
5. Connection type? (eg: dialup, broadband, cable, etc.): Broadband.
6. Modem & router brand name & model numbers? (eg: Linksys WRT54Gv4): Belkin Wireless 802.11g (I hope i helped there :S)
7. Where are you trying to connect from (house, appartment complex, school, student accomodation, work, etc.)?: From my house.
8. What version of LimeWire (LW) & Java do you have? (Go to LW's menu Help bar > About LW...) Will show both LW & Java version.: Limewire version 5.0.11 and Java version 6.
9. Who is your ISP (Internet Service Provider)? Bigpond broadband.
10. Do this simple test for us. Using your browser go here: http://www3.limewire.com:6346/ The page should say 'Your test worked!'.: It says Your test worked! just that single sentence.
11. Are you sharing the connection with other computers or p2p sharing programs? If yes, please give details of set up.: I am sharing the internet with my computor through the router only other p2p sharing program i can think of that i have is Bittorent.
12. Is this a your 1st try at LW or is this a new problem with an experienced user. This is a new problem with an experienced user (had some small problems like this just closed and opened limewire and it worked).
13. Do you see a brick wall in front of the blue world icon at the bottom of LW's interface?: I use LW5 so when i go into advanced tools it says you are behind a firewall.
14. For those using a modem/router, how is your modem/router set up...are you port forwarding or is UPnP enabled?: umm well my router is connected to the modem and the phone port, i beleive UPnP has always been working as this has only been a problem recently and ive never port forwarded before.
15. What security programs are you using (antivirus etc)? Some people might not be aware that their security suite includes a firewall. Norton 360.
16. What country are you living in? Sometimes there are ISPs with the same name in more than one country (eg Clearwire in the USA & also in Ireland).: Australia.
17. uNo my setup with my router and modem has not changed, Since this problem began i updated my limewire to LW5, I have updated my java before though there was no problem when i did, no i havent added any new software, I have not moved houses and i have not changed my internet plan.

I hope i was some use of help there

In my attempts to fix this problem I have done the following.

Uninstalled and reinstalled LW.
Checked my firewall to see if it was letting LW5 through (it says it was).
I removed the rule in my firewall and readded from scratch.
I have disabled performance options (Ultra, TLS DHT).
I have disabled OOB.
I have deleted trash from the incomplete folder.