I have a request to get a restored SharePoint 2010 up for some recovery. The existing SharePoint is still running while having its same Image restored to a separate Server, the first key important thing is that the cloned Server should not have the same Host Name as per the existing one.
Once you boot up the cloned Server, the HostName is changed and you will hit Error when connecting to SharePoint configuration server.
So, if you run SharePoint Product Configuration Wizard, You will hit error again saying you cannot connect to existing Config DB. Simply because your cloned server is still pointing to OLD Config DB (OLDHOSTNAME\SQLInstance).
What you can only do! (as far as i know!) is to run the following STSADM comment
stsadm.exe -o setconfigdb - -databaseserver "<DatabaseServer>" -farmuser "<DOMAIN\YourFarmAccount>" -farmpassword "<YourFarmAccount Password>"
Once its done, rerun SharePoint Product Configuratino Wizard…