Use a GPO with a Computer Startup script to do so. The only other GPO
setting that is available is the ability to change the "name" of the local
Administrator and Guest accounts.
I found a script that would do that but computer startup script can't handle
it, so I'm thinking I'll have to use Logon scripts. Then there's the issue
of how to force it to run even if the person logged on does not have Admin
rights.