I found the following article on MS support site during sqlserver2000 personal edition setup. It's this article that should have solved one of my problem long before.

Q:Can I rename the server after installing Sqlserver2000?

A:Yes. You can. The Sqlserver2000 service will identify the modified name automatically during its first startup after renaming. But you must do addtional steps to update the sysservers table.

 

As to the default instance:

sp_dropserver <old_servername>
go
sp_addserver <new_servername> , local
go

As to the named instance:

sp_dropserver <old_servername\instancename>
go
sp_addserver <new_servername\instancename> , local
go

BTW:the MS support site has silverlighted~