Hi Homer,
I will try my best to assist with some of these questions. In order to assist we would need to know some things (you may want to open a ticket with your support group and have the following information handy to formulate the best plan for recovery. It is good you are addressing this before the crisis strikes.

How did you take your snapshot of your environment?

I am not sure how you captured the environment and what you are doing to test it?

If you are using a snapshot of your current production environment and then trying to connect it to the same DB, you run the risk of corrupting all of your projects. Are you connecting to the same DB or a different one for your testing?

Has this environment snapshot ever worked for accessing and if not what is the error you are receiving?

Quite frequently what happens with LDAP is if the connectivity is broken then the authentication needs to be set back to QC AUTHENTICATION and then log into the system to re-establish the LDAP connectivity through the Site Admin. I have uploaded the document on how to change that authentication (it will need to be done on the back end in the DB for quality center and then use the qcadmin account and password that was used to install ALM, and not a basic user account with admin privileges).

There should be no special files or configurations that are needed other than the ones that are established during the LDAP configuration within ALM.

In order to reset the admin user information and credentials see the following post:
http://eyeontesting.com/questions/15975/we-dont-know-the-admin-user-account-or-password-fo.html

I hope all this helps get you on the right track to a successful data recovery plan of action.

Dan