msconfig went AWOL, machine won’t restart or shutdown

I must’ve disabled something that results in a “Windows cannot find ‘msconfig.’ Make sure you typed in the name correctly, and then try again. To search for a file, click the Start button, and then click Search.”
It’s a Windows XP SP2 machine. Downloading MSCONFIG.exe, I located another post herein which stated were to put that file, so now I can bring it up via RUN. However, the resultant click on Restart does not cause the machine to restart, nor does trying to either Restart or Shutdown from the Start menu.