In exploring my Windows 7 Ultimate, I found Start > Administrative Tools > Windows PowerShell Modules. Upon activating the link, the following appeared in a window:
Windows PowerShell Copyright (C) 2009 Microsoft Corporation. All rights reserved.
WARNING: File C:\Windows\system32\WindowsPowerShell\v1.0\Modules\PSDiagnostics\PSDiagnostics.psm1 cannot be loaded because the execution of scripts is disabled on this system. Please see "get-help about_signing" for more details. PS C:\Users\Gandalf>