For example, you should use this line if you want to launch a *.ps1 PowerShell script externally from outside PowerShell via desktop shortcut or from inside a batch file:
powershell.exe -nologo -executionpolicy bypass -noprofile -file "C:\myscript.ps1"
Use this to simply execute a PowerShell command:
powershell.exe -nologo -noprofile -command Get-Process