Can not start RPC on a domain server

Hello,
I set the Remote Procedure Call service to log-on to run under a specific
user. After restarting the server the service stopped running. It would not
let me access the property so check the log-on option to “Local System
Account� option under “Log On� tab and uncheck the “This Account�. When I
tried to start it goes half way and it comes up with this error message:
“Could not start RPC service on the local computer. Error:1057. The account
name is invalid or does not exist, or password is invalid for the account
name specified.� But none of the suggestions in the error report are true. Is
there another way to start the RPC service. I tried “net start rpcss� from
the command prompt but did not work either.
Thank you for your help.
-Z