Add a computer account to AD Sites?

I am struggling with a problem with my win 2000 network, and win 2000 clients’ logon process. For some reason some win 2000 clients will authenticate to a DC over a slow WAN link, when a very free DC is available. The login process will take about 5min to complete in that case! Everything I read about this problem points to adding the user account, and the computer account in AD to Sites and services section of AD. The porblem lies in that when I try to use the ‘move’ function in AD Users/Comps, Sites/Services containers arent available to place the account into. From Sites/Services and selecting the ‘add’ function, it only has DC’s in the list. Does anybody know how to add a user or computer to AD sites/services?