After updating, there is no network setup. This machine has been in constant use running 8.10 but clicking upgrade has broken the network. The real problem now is that unlike 8.10 the new GUI cannot be used to setup the network - or more likely we just don't understand the new GUI. Either way, we cannot configure the network. I am very familiar with our network's setup but to no avail. Any hints are welcome as this is (was) a much used machine and we need to have it operational.

PS: Yes, I tried the Ubuntu forums but without any luck. (so far)

Have you tried booting the previous kernel? That is something that will happen every once in a while, kernel updates breaking some functionality. It is why updates tend to leave at least one older kernel on the system.

Anyway, you may need to edit /etc/network/interfaces if an older kernel is out of the question:
http://www.cyberciti.biz/faq/setting...terfaces-file/

I set up the network by hand (good practice!) and we're back on the net. The core problem is still unknown to me and the total inability of the new GUI to configure the machine is quite a surprise, to say the least. I'll try the preveious kernel later. That could be a better solution. Thanks.