Get-Help : A parameter cannot be found that matches parameter name 'showwindow'.

I've updated to PowerShell version 3 on my Windows 7 SP 1 system.  When I tried to run

PS M:\> get-help get-service -showwindow
Get-Help : A parameter cannot be found that matches parameter name 'showwindow'.
At line:1 char:22
+ get-help get-service -showwindow
+                      ~~~~~~~~~~~
    + CategoryInfo          : InvalidArgument: (:) [Get-Help], ParameterBindingException
    + FullyQualifiedErrorId : NamedParameterNotFound,Get-Help

I've tried uninstalling and reinstalling with the same result.