DHCP service will not start

Hello all. I have a windows2003 domain running server 2003 ent r2. two weeks ago my dchp server stopped handing out IP addresses. I was not able to get dhcp running again on either of my DC's. I was however able to start dhcp on a member server. The error I get on the DC is "user account already exists". I am using the local system accout to start the service. Any ideas? Microsoft says "No known solution for this error?....of course.