Hi, and welcome to LQ.
My only advice, after seeing your post here for a few days, is maybe you should post your question in the networking/wireless section where the net gurus may be able to help.
BUT, check the file /etc/resolv.conf
This file is configured on the fly by the daemon resolvconf and sets the nameserver.
Sadly, I have found it to change and (also) lost connection because of it.
You can disable it(if necessary) by going to "Configure your computer" system/Managing system services... from the menu button. you need to be root. I would check the nameserver address first (maybe /etc/resolv.conf~ has the info you need), edit /etc/resolv.conf and then turn off the daemon as above.
I hope that is what you need.