Distributed Transaction Cordinator

I have a problem with the Distributed Transaction Cordinator service. The service will not let me make any changes to it in properties gives access denied error. It also does not have log on as local system. I was wondering if anyone new of a registry setting that could be modified to set the service back to its original state. It seems as though the system is controlling the service and is using up most of the system resources. This is a Windows 2000 Server. Please help I need to get this fixed asap.