INTERNET CONNECTION SUDDENLY LOST

(All details pf system etc at end of message.)

Hello all. I understand that there are some really bright sparks out there! Shine on me for a while.....

Problem is this: We have two Windows XP computers that have been working wonderfully off the wired hub that connects to the broadband ISP. Both computers communicated well with each other and I connected a third computer yesterday and it too immediately connected to the home network and connected to the internet. All looked perfect until I was downloading some music files from Limewire. The internet connection was lost and continues to be lost on only this one computer inspite of all my efforts. This computer can still connect to the other 2 computers which can both connect to it and to the internet.
I am sure this is a simple thing - but even simple things are complex for simple man!
If you can help, I would be grateful.
Joe

1. Windows XP Professional
2. Windows firewall
3. Lots of RAM
4. Lots of Hard Disk space available
5. Broadband.
6. ATA (VOIP) "switch/router?"
7. Connecting from house
8. LimeWire 4.14.12 & Java 1.6.0_03
9. ISP is a Spanish co. called Broadband4Spain based in Cómpeta bear Málaga.
10. Do this simple test for us. Using your browser go here: http://www3.limewire.com:6346/ The page should say 'Your test worked!'. What happens when you go there?
11. On a home network. All (3) computers connected to a wired hub then to the ATA (VOIP) box that goes into the wall and connects me to the internet and telephone via a satellite dish. fast 100Mbs (?) connection.
12. I was downloading from LW for the first time on two computers simultaneously on the home network. One continued to download and it and the third computer (from which I was not downloading at the time) still connect to the internet. It is the other computer on which I was simultaneously downloading from LW that simply stopped mid download and has not reconnected to the internet since
13. There is a brick wall in front of the blue world icon at the bottom of LW's interface
14. The computer I am on now is using PPPOE so I guess I'm using an ethernet and ADSL??? I don't know whether the other (faulty) computer is using the same but I assume it is. I don't understand what port forwarding or UPnP enabled are - sorry!!
15. Using AVG professional antivirus and Windows SpyWare. They have always worked fine before and allowed LW to download during the short time that I have been doing so.
16. I am currently in Spain
If there is anything I have missed, please let me know.