We recently did this because of the load the original SQL server had, I'm not a DBA, so I can't give you the exact steps, but basically we took the VC Service offline, our DBA did a copy of the VCDB to a new SQL server, this preserved all data including the unique signature that VC has with the database and all the accounts/password. This literally took less than 15min, then like it was suggested, change your DSN to point to the new SQL database, in this case you're just modifying the SQL Server, everything else stays the same, do a test login and if that works, start up your VC Services. You do not need to create a blank VCDB and I'm wondering if that caused an error as that becomes a different instance than the one you had because I believe theres a special signature it creates for each VCDB instance. You should really just replicate using SQL tools and just install a new VC if you need to and just create a DSN pointing to SQL Server.
