Unidentified Network problem

Good evening all

I have just received a new Dell Inspiron N5030 and it has developed a network problem.  Initiallly the wireless internet connected to our home broadband network with no problem and worked for approx three days.  It then dropped out of the network and came up with a 'Unidentified Network' issue, I have spent a long time on the phone to O2 the provider, and Dell support , India I think, who tried various things in the 'run' section.  I am using Laymans terms as I am vedry inexperienced with this sort of thing. THe internet does not connect even with the cable plugged in direct now.  It seems to be something to do with me needing to be linked to the 'home' network and not a 'public' network as the internet connections is present but I cannot access it.

I hope I have made a little bit of sense and someone can help!

Regards, Neil