If you need to know some of the system variables that are already set you can run this script to get the values
Get-Childitem env: gci env: | sort name
Once you know what variable you want you can do something like this
Write-Host "Computer:`t" $env:COMPUTERNAME Write-Host "Domain:`t" $env:USERDOMAIN
All information on this site is shared with the intention to help. Before any source code or program is ran on a production (non-development) system it is suggested you test it and fully understand what it is doing not just what it appears it is doing. I accept no responsibility for any damage you may do with this code.