Unable to run any program on the server

Hi, We’re running Windows 2000 advanced server with service pack 3 on our intranet server. I was trying to restrict some of the programs to run from the server, but by mistake I pressed “OK” without adding the programs and after that nothing is “OK” it has restricted all programs to run from the server, not even MMC.

I would appreciate the quickest possible response as this is a production server.

Thanks in advance,

Hassan