Although you're logged on to an administrator account, you need to run the SFC program under elevated rights. When the User Account Control message appears, just click "Continue". OTOH if you are logged on as a standard user, enter the appropriate credentials, and then click Submit.

See also:

Windows Vista Help: How do I allow an application to run once with a full administrator access token in User Account Control?:
[url]http://windowshelp.microsoft.com/Windows/en-US/Help/1c3e6b36-b65a-42ed-8bb0-0868ef13c0751033.mspx[/url]


--
Regards,

Ramesh Srinivasan, Microsoft MVP [Windows Shell/User]
Windows® Troubleshooting [url]http://www.winhelponline.com[/url]
Winhelponline.com blog [url]http://www.winhelponline.com/blog[/url]


"jihchiang" <dhuang1@cogeco.ca> wrote in message news:8FA0E4E0-8541-4308-BFB6-5079D7E7537A@microsoft.com...
One last question before I give it a try. The " run as Administrator "
worries me, because as I understand it "run as " is not the same as being
the Adm. Since I am the Adm., do I have to change back as the Adm.
afterwards ?
"Carey Frisch [MVP]" <cnfrisch@nospamgmail.com> wrote in message
news:u3V3%239vgIHA.1164@TK2MSFTNGP02.phx.gbl...[color=blue]
> In the Start Search box type: CMD
> When the Command Prompt appears, right-click on it
> and select "Run as administrator", then type in SFC SCANNOW
> in the Command Prompt window and hit Enter.
>
> --
> Carey Frisch
> Microsoft MVP
> Windows Shell/User
>
> ---------------------------------------------------------------
>
> "jihchiang" wrote:
>
> In one of the questions I asked, someone ( I think it's Bob ) suggested
> sfc
> scannow. I didn't get to use it as the problem was solved. Today I tried
> it
> just for curiosity. I opened Start menu, enter sfc scannow on the search
> box,saw the program name at the top, right click then click Open. NOTHING
> happened. What did I go wrong ?
>[/color]