SQL Server Express
when doing this kind of "sorcery", please be carefull when "re-registering" the database..
just to cross check, usually you should:
-detach the original db;
-copy it elsewhere or rename destination files (mdf, ldf and eventual ndf) say, with your prefix.. (orig.mdf becomes clone_of_orig.mdf and the like);
-reattach the original db via
USE [master] GO CREATE DATABASE [myDB] ON ( FILENAME = N'C:\Program Files\Microsoft SQL Server\MSSQL.3\MSSQL\Data\myDB.mdf' ), ( FILENAME = N'C:\Program Files\Microsoft SQL Server\MSSQL.3\MSSQL\Data\myDB_log.ldf' ) FOR ATTACH GO
-the original logical db name is correct, as the original physical file(s) pointers..
-attach the cloned db via
USE [master] GO CREATE DATABASE [CLONE_of_myDB] ON ( FILENAME = N'C:\Program Files\Microsoft SQL Server\MSSQL.3\MSSQL\Data\clone_of_myDB.mdf' ), ( FILENAME = N'C:\Program Files\Microsoft SQL Server\MSSQL.3\MSSQL\Data\clone_of_myDB_log.ldf' ) FOR ATTACH GO
as you can see, the logical name of the db is different, as are the referenced phisical file names..
-the internal logical names of each physical file are not considered to collide with other database's logical names, so you are not in trouble here..