'Failed to connect to SQL Server (local\TACVISTA). " Login failed for user 'xxx\xxxxx'. Reason: The account is disabled." message appears when trying to install Vista using another account than the account that is logged on to the server.
TAC Vista 5.1.X
The TAC Vista installer SQL configuration settings page states 'Select authentication and specify SQL Login or Windows account and password to set how TAC Vista Server will access the SQL server.' This means how TAC Vista will access the SQL server when Vista is running, not during installation.
Ensure that the user running the TAC Vista installer has the correct permissions to install an SQL server (if this is a new database) and configure it. The specified user will be used during runtime, but the launching user during installation. The installing user can then be removed from the SQL server security settings after installation is complete.