ng.ps1 is not digitally signed. You cannot run this script on the current system code example

Example 1: ng : File C:\Users\Sriram\AppData\Roaming\npm\ng.ps1 cannot be loaded because running scripts is disabled on this system. For more information, see about_Execution_Policies at https:/go.microsoft.com/fwlink/?LinkID=135170.

deleting ng.ps1 everything was going in perfect way

Example 2: ionic.ps1 is not digitally signed.

Set-ExecutionPolicy -Scope Process -ExecutionPolicy Bypass