Set-ExecutionPolicy : Access to the registry key 'HKEY_LOCAL_MACHINE\SOFTWARE\M icrosoft\PowerShell\1\ShellIds\Microsoft.PowerShell' is denied.

Resolution for this :

* Run: regedt32
* Goto HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\PowerShell
* Right-Click > Permissions
* Select, and add your account, grant it "Full Control" privileges

It helped me out, being "alternative" admin, on my machine, which was prepped by an operations 

admin

Reference : 

http://answers.microsoft.com/en-us/windows/forum/windows_7-windows_programs/access-to-the-registry-key-for-powershel-is-denied/9e5cb142-ee69-e011-8dfc-68b599b31bf5