Problems with wifi

I have Dell Inspiron14z Ultrabook running windows8 which came preinstalled.

I do not know if this is a hardware or software problem. Sometimes, the internet connection disappears.

Most of these times, when I rt. click on the network icon, and then click on 'troubleshoot', windows reestablishes the connection. A message appears: 'Resetting the Ethernet modem. A network cable is loose or broken'. There is no cable connection between the computer and the router. Does is mean a cable inside the computer is lose?
However once, the wifi signal was not restored, but restarting the computer solved the problem.

I shall be grateful for any help in this matter.

Thanks,
Preet