What should I check if the Wi-Fi doesn't work?

pu1. Sometimes the internet might be disconnected, so I think that's why it's not working

2017-12-06

OK

pu2. Turn off the router and turn it on again. If the Wi-Fi is working but the internet isn't working, I think we can contact the internet company

2017-12-06

OK

pu3. Turn off the router completely, turn off all connections to the computer, and try to reconnect in a minute or so

2017-12-06

OK