When you are using NETWORKSERVICE, are you providing a username and password or leaving these properties blank?

>Thanks Cathi for replying...
>Yes I set the password and domain ect. I just cant figure out why my service quits running when I log off the machine via Remote Desktop. I tried it as local system but couldnt get the service to produce the results that I desired. When I changed the service to NETWORK SERVICE, I got the error when I was installing the service that the username/password was invalid. I was not prompted to set a user/password. Do I do that programatically for network services?