Unable to connect to Internet ' Wireless capability turned off and wont turn on'.

Recently I got a memory module from Mr Memory (formerly Crucial, I think) for my Dell Inspiron 15, 5000 series, Windows 10,  having asked for a suitable one.In my laptop there is one memory slot so I tried this having extracted the original memory. However it did not work. So I  I put back the original module to find that I could not connect to the Internet.

 I ran the troubleshooter and was told 'wireless capability' is 'turned of'f. To remedy this . I  went to 'WiFi (in 'Settings) ' where WiFi was signaled 'off'.   I clicked  the  'On/Off' button. It immediately moved to 'On', but  after 4 seconds switched back to 'Off'.  It refuses absolutely to settle on ON, but virtually immediately returns to 'OFF'. . The airplane symbol had appeared on my taskbar, but all efforts to shut it down (going to Notifications and click the on/off button) did not work.(There is no problem with the Internet in my station - as I am working with another laptop; I also rechecked the laptop case to see whether anything was out of place or disconnected).   Am not sure what to try next. .