Powershell cannot be loaded because execution of scripts is disabled on this system.

Everytime I need to run a powershell script I forget to set the ExecutionPolicy

Set-ExecutionPolicy Unrestricted

This will let you run the script without the error. Be warned you do this at the risk of it not being from a trusted source.

Get-ExecutionPolicy

This will tell you what your current session is running at.

Source:
http://technet.microsoft.com/en-us/library/ee176949.aspx