File C:\Users\Dell\AppData\Roaming\npm\ng.ps1 cannot be loaded because the execution of scripts is disabled on this system code example

Example 1: ng cannot be loaded

run the below command 

Set-ExecutionPolicy -ExecutionPolicy RemoteSigned -Scope CurrentUser

Example 2: The file C:\Users\user\AppData\Roaming\npm\ng.ps1 is not digitally signed. You cannot run this script on the current system. For more information about running scripts and setting execution policy, see about_Execution_Policies at

Set-ExecutionPolicy -ExecutionPolicy RemoteSigned -Scope CurrentUser