I can not figure out how to rename a db in sql 2000.

I'm trying to rename the database by logging on to isql from a command prompt and the typing in

GO EXEC sp_renamedb N'CMS200_V25_MSSQL'; N'CMS400_MSSQL' It does not work ir returns nothing it just goes to 2> _ I have also tried it with out the N in fornt of the dbs. What am I doing wrong? The database is in single user mode.

Please help.