I had a similar problem with my Lenovo Z570. There are two potential issues going on... One is related to hardware, the other software.
For the software end of things, your laptop is most likely suffering from "Multiple WiFi Personalities". Basically, the way I understand it, Ubuntu is not clear on which wifi drivers should be loaded based on incompatibilities with the hardware (this is just how I understand it... I could be wrong =).
The simple & temporary test is to blacklist "acer-wmi" (from terminal):
sudo rmmod -f acer-wmi
sudo rfkill unblock all
rfkill list all
if that stets all of your blocks to "no", you are in business... simply edit your /etc/modprobe.d/blacklist.conf file to blacklist that item and you are good to go.
sudo gedit /etc/modprobe.d/blacklist.conf
When the editor opens, add blacklist acer-wmi as a new line at the end of the file. Save and Exit. then type in the following just to double check things:
rfkill list all
If you still see any "Hard blocked: yes" entries at this point, you have one of three things going on. Either your physical wifi switch is in the off position (if you have one... my z570 has it on the front bezel), your software switch is off (Fn+F5 on my z570) or you may need to simply reset your Bios.
For me it took resetting my Bios to fix it. Simply restart your laptop and press F2 at boot up. Once in the Bios, press F9 to reset the Bios, followed by F10 to save and exit. Test your wifi now. If it's working, you can now head back to your bios and get things setup the way you like them again.
It took a TON of digging and trial and error until I finally got this working. I hope you don't have the same perils!
