Receive Error 8007000b

I need to do the instructions below for an error I am getting on updating. however, when I type CMD in search box I don't get any options to run as administrator and if i just type the command it states I have to be the admnistrator - how do I get around this..I am infact the only account user on my lap top, and performall tasks so why does it think I am not the administrator?

Windows Update error 8007000b: if you receive error 8007000b when you try to install Windows Vista updates, the Windows file system transaction log has become corrupted. The transaction log is used by the Windows file system to recover when a file error occurs. To correct this update error, you need to clear the log. Here's how: To clear the file system transaction log

1.Click the Start button. In the Search box, type Command Prompt, and then, in the list of results, right-click Command Prompt, and then click Run as Administrator.

2.In the command prompt window, type fsutil resource setautoreset true C: (This assumes that C: is the drive in which Windows Vista is installed. If Windows is installed on another drive, change the drive letter accordingly.)

3.Restart your computer.

4.Download and install the update again.