Clone New Database From Existing

How do I go about creating a cloned copy of an existing database on the same server? I basically want to set up a test copy of a production database, but let it reside on the same server with a slightly different name, prefixed with 'Testing_".

I typically just use Studio Express Manager and not scripts to do admin tasks. Here's what I tried that didn't work so well:

* Had full backups of production db
* Detached production database I wanted to clone
* From within Win Explorer, copy the .mdf and .ldf files within same data folder and gave them a new name, prefixing with "Testing_"
* Re-attached prodution db
* Attached "Testing_..." database

Sql Express seems confused at this point with new database I attached. It references the full path of the database I copied from (c:program filesmicrosoft sql servermssql.1data...". I rename the datbase, removing full path and prefixing with "Testing_".

* Using Sql authentication, changed the default database for the Login account to the new cloned copy of database.
* Did some query level data sanitizing to the cloned copy of the db. I am positive I performed this on the correct db.
* Was able to connect/authenticate to the cloned copy through a custom VB app on my dev machine, and all looked well.
* Tried to connect to the cloned db from another machine and couldn't. Went back to my dev machine and noticed the original production db looked hosed -- there were no tree nodes available to it! Was still able to connect to the cloned "Testing_" db copy, but not able to connect/authenticate anymore to the production copy.
* Detached cloned copy of "Testing_" db and moved it out of the data folder.
* Detached production db. Got an error msg indicating operation failure of some kind, but the database was gone from the tree.
* Reattached the production db but couldn't hit it from my custom vb app. Re-did the login and user accounts used by the app and was able to hit it. However, the data sanitizing I had done earlier in the cloned copy clearly was visibile in the production db!
* Had to restore production db from backup. Had problems authenticating from app, and recreated User account before the app was to connect.

Q1: What I am doing wrong? Sql Express was obviously as confused as me somewhere along the line.

Q2: Is specifying a default database used by a Login account necessary for a VB app like mine. I think it was something I discovered in the past, however, this would seemingly present a problem whenever I want my app to hit a different database, established through a connection string.

TIA...

Rick