I’ve had this problem a few time over recent weeks, all with Windows 10. The wireless and/or wired card appears to be connected but the system cannot access the internet.
There are a number of things to check.
(1) If wireless connected ‘forget’ your wireless setting in Windows and re-establish it.
See http://www.thewindowsclub.com/forget-wireless-network-profiles-windows-10 if you don’t know how.
(2) There appears to be an issue with Windows 10 update that causes this problem (I’ve even had this happen at home). To fix this run a system file check with repair at an admin command prompt. You can also try running a DISM command. Here’s how http://www.howtogeek.com/222532/how-to-repair-corrupted-windows-system-files-with-the-sfc-and-dism-commands/
(3) Repair the Winsock libraries. To do this open a command prompt with admin rights (see above) and type:
netsh winsock reset
Note: I’ve had three instances of this in the past month so this may be worth running as a first fix.
(4) Windows refresh. If in item 2 above you receive a message informing you that there are problems that cannot be fixed then you will need to do a windows refresh. Hold the shift button and press restart. You can then select troubleshooting mode to do a Windows repair.