In which case, this might help
Can you hiobernate your PC, then boot it again? So it's all not working? Then, in the Start Search box, type "cmd" and hit enter, this brings up the command prompt. I want you to then type the following commands, one per line, hitting Enter after each one:
ipconfig /release
ipconfig /renew
Tell me, does this solve your problem? If it does, we can put this inot a batch file, which you can then use as a temporary workaround.