First, I must mention that I am not good in English and therefore uses Google translate here. Hope it goes pretty smoothly.Have a laptop Lenovo thinkpad edge E520 which I installed Linux Mint on and everything worked perfectly until the last upgrades. After the restart, I had no internet anymore. Have tried both cable and wireless unsuccessfully. Down near the clock, I see that the network cable is connected and when I take the cord out changes the icon to the wireless symbol.So this shows that the Internet should work as it shows the cable or wireless icon near the clock. But for some reason can not make the rest of the software to see this. The browser is not able to connect to the network and when I run the upgrade program, it will find neither the internet. Have TeamViewer on it and it does not work as it can not connect to the net.However, as stated then displays the icons down by the clock that the laptop is connected to the network, either on cable or wireless. Have tried rebooting several times and one time everything worked and it was on the internet. But it was just the one time. Unfortunately I am no expert when it comes to Linux and have just installed this on a laptop to test it. 
The programs can not find the Internet
internet;thinkpad