So you've lost all networking?
Have you checked the network manager icon in your system tray, to see if networking has been disabled?
All you need to do is right click on the sys-tray icon for network manager in your desktop and check that networking is enabled and that wifi is enabled.
I have seen this happen a few times - where someone has accidentally disabled networking, or an update has somehow disabled networking and simply re-checking those options has fixed the issue.
However, if the network manager says that networking and wifi are already enabled, but you still haven't got a connection - then there might be something else going on.
In which case, if you could post some more details on your PC hardware and we can help to troubleshoot the problem further!