After taking Mack 56's advise of 14th Feb. and finding it worked I now find that it only worked on two occasions and doesn't any more, alas.
Problem is that when I start a search a message appears reading "Limewire currently connecting to the internet. Your search may not return many results until you are fully connected to the network" The search carries but yields no results.
The connection quality shows "you are currently connected to the network" (not strongly connected) and the firewall status shows "Limewire has detected a firewall".
I have tried with windows firewall switched off and Nod32 anti-virus both on and off all with same result.
Seems as though I have another firewall I didn't know about?
System details:-
1.Windows XP
2. Windows (AOL switched off)
3. 512mg
4. 96gig
5. BB
6.BT105 modem
7.house
8.Limewire 4.16.6 Java 1.6.0_03
9.AOL
10.worked
11.no
12.new problem/experienced user(well,fairly often)
13 yes
14. UPnP
15 NOD32 (tried both on and off) 16. UK.

Any help would be appreciated before I cut my losses and head for Pirate Bay!

Have you tried any of the fixes in the thread below? Start off by deleting LW's preferences folder & if that doesn't help, try the older version of Java, or try changing ports (details for all in thread below). Do these things before the other fixes in that thread.
If LW Will Not Connect

Have you been able to connect with older versions of LW? Did the connection problem start after installing the latest version?

If nothing helps, you could try the latest LW Beta verison & see whether that's any better ('get Beta' button on the right side of the main download page).
Lime Wire » Download LimeWire
Remember to use the offline installer...when you click on your download platform, cancel the dialog box which pops up. Now use the option to download the offline installer.

My thanks go to Birdy and to Skyliner, who both pointed me in the direction of replacing the Gnutella.net file. Thanks to them I now have a very strong connection and no annoying brick wall.