SQL 2012 won't start SQL Agent nor initialize the EventLog

Hello, 

I have a SQL 2012 Standards 64bits on top of a Windows 2008 R2 SP1 acting also as Domain Controller. Servers is installed in C:\Program Files\... . Default instance is installed in D:\SQL Databases\MSSQL11.MSQSERVER\....

Couple of issues:

1) The SQL Server Agent fails to start. The service management reports that the SQL Server Agent didn't respond in a timely fashion to the start operation. No logs, etc..

2) In the SQL Server logs, the server's reporting errors initializing the Event Log system. 

Error: 17156, Severity: 16, State: 1

initeventlog: Could not initiate the Eventlog Service for the key 'MSSQLSERVER', last error code is 5.

Help will be appreciated :)