I have two laptops running Win 10. One is a Dell Latitude E5470, which is about a year old. The other is a Microsoft Surface Book Pro, which is just a few months old. I also have two very old machines running Win XP. One is a Dell workstation and the other is a Dell laptop. I am in the process of moving several mission-critical apps from the old machines to the new ones.
All 4 machines are most frequently used in our home office, which is also where the wifi router is located, so the signal is strong. The two old machines work flawlessly with the local wifi network. Until recently, so did the new machines.
I had a little problem with the new machines going into airplane mode, but that has been resolved.
The Surface Book connects to the local wifi automatically whenever it is turned on. The new Dell laptop used to connect to the local wifi, but would lose the connection if it went to sleep or shut down. Then I had to manually reconnect it. Every time I did, the wifi dialog showed that the "Connect automatically" option was checked, but it did not connect automatically.
Today, I was fiddling around with it in the hopes of getting it to connect automatically. I decided to delete the local wifi connection and re-enter it. Now I cannot get it to connect at all. When I select it from the list of available networks, it asks for the "Network security key", which I assume is the password. When I enter it, I get a message saying "Cannot connect to this network". I am pretty sure that I am entering the key correctly, because I tried entering it wrong and I get a different message saying that the key is incorrect.
Can anyone suggest what I can do to get it working again and connecting automatically?
I can attach screen shots if that will help. Let me know what shots are needed.