Look at the solution here
http://ask-leo.com/why_cant_i_enable...n_command.html
Ilknur Nese TUNCAL
<>, haber iletisinde sunlari
yazdi:236a8670-cb54-4b3b-bd0b-...
>I am using MS Windows Vista Business, when I log on as a user and try
> to run the command prompt via the windows logo + R keys I get a window
> with 'This operation has been canceled due to restrictions in effect
> on this computer. Please contact your system administrator."
>
> I have checked the permission on the command prompt and my username
> has full control.
>
> If I run the command prompt from the accessories its ok, no
> restrictions.
>
> I am going crazy trying to figure this one out, any help would be very
> much appreciated.
>
> Thanks