Hi my name is ***** ***** I will be the expert working with you today to help resolve the problem you have posted.
I am sorry to hear that you are facing problem with your windows 10 Cortana and start menu button not working.
let me know when you are ready we will follow troubleshooting steps
If Cortana and Windows menu key is not functioning then you may follow the steps given below
open control panel using this method
press Ctrl Shift and Esc keys together it will launch task manager click on file and select run new task now type in control.exe and hit enter.
Control panel will be launched now on the control panel windows click on the search box and type in recovery and hit search you will see the first icon as recovery click on it, after that you click on the link below on the same window “If you are having problem with your PC, go to settings and try resetting it”.
Now you will see 3 options Reset this PC should be selected by clicking on the Get started button under it.
This will fix your Cortana and windows start menu launch button functions.
Hope this helps.