You may try a couple of steps to get the computer up and running
Go to Windows - Settings, Update and Recovery, Recovery
You have 3 options there 1.Refresh 2. Reset 3. Advanced startup.
Select the 3rd option, Click "Troubleshoot" , In the next scree if you have 3 options 1.Refres 2.Reset 3.Dell backup and recovery, Pick the 3rd option and proceed further. That should fix the issues.
Type "slui 4" , That opens up a new window for Phone activation, Select your country, Dial the number given there, follow the instruction. that should work.
Please respond incase you need any further assistance.