Inspiron 3650 cannot connect to internet.

Folks, I just recently purchased an Inspiron 3650 and am having fits getting it to connect to the internet, via a local wi-fi network.  I am using Mozilla Firefox and was able to get on the internet yesterday. Before that, a day or two prior I had to use an external USB wi-fi adapter and was able to get on the internet.  Now I cannot get on regardless of using the onboard wi-fi adapter or external USB wi-fi adapter.  If using the onboard adapter the desktop shows the internet connection with a yellow triangle and an exclamation point and when I open the connection it states "no internet, open".  If I try the external USB adapter the yellow triangle disappears and when I pull up the connection, it shows as wi-fi2 and states "connected, open", but I still can't get on the internet.  I've tried running diagnostics on the onboard adapter, tried updating the drivers, but can't due to no internet.  Going to device manager and checking the drivers, it states that the best drivers are already loaded.  I'm wondering if my local wi-fi network might be the culprit as I recently purchased two identical laptops (brand new, won't mention the brand) as Christmas presents, which worked great the very first time I fired them up.  They were able to get on the internet to get Windows 10 up and running.  After I shut them down, nothing!  When I started them up the next morning I couldn't get on the internet, even using an external USB wi-fi adapter!  Extremely frustrating!