Since loading 18.04 on my Dell Inspiron laptop the wifi connection to my home router has been very erratic. Whenever it lost the connection I would test the connection with my tablet which would invariably work (not always, I do sometimes have a problem with the landline internet here in France). I have been using 14.04 for the last year and only ever had problems when the router itself would cut out for a few seconds. Again, I used to test this with my tablet to make sure it wasn't the computer running 14.04.
When I lose the connection now the wifi symbol changes to a question mark. Since my tablet works I assume this means that the computer isn't recognising the signal from the router. To make it more confusing I just tried to tether my phone to my laptop, again something I did often with 14.04 with no problems, and though this time I got the wifi symbol, it still wouldn't connect to the internet.
I previously asked another couple of questions, but someone merged them with some earlier questions of mine far down the list so they have disappeared. Maybe I should ask them one at a time when I have sorted out the wifi.
Thanks for any help.