"The variable is read only by default, but can be removed with the -Force switch to Remove-Variable. To make your change persistent across sessions, you can make a profile file which is much like a .bashrc (For bash on Linux) except for Powershell.
In your Documents directory (normally C:\Users\YOUR_USERNAME_HERE\documents) for your user account, create a WindowsPowerShell folder (named exactly like that) if one does not already exist. Inside the folder, create a text file called profile.ps1 (ensure it's not profile.ps1.txt).
Inside the file, place anything you want executed when you open Powershell.
example:
Write-Host ""Hi John, welcome back!"" Remove-Variable -Force HOME Set-Variable HOME ""C:\Users\khornsby""
