I have a SQL Server 2008 SP1 installation. Everything was working until I changed the password of the user that starts SQL Server and SQL Agent.
This is my SQLAgent.out file.
2011-08-10 10:47:45 – !  Unable to connect to server ‘(local)’; SQLServerAgent cannot start
2011-08-10 10:47:45 – !  SQLServer Error: 160, Specified driver could not be loaded due to system error 193: (SQL Server Native Client 10.0, c:WindowsSysWOW64sqlncli10.dll). [SQLSTATE IM003]
2011-08-10 10:47:45 – !  Logon to server ‘(local)’ failed (DisableAgentXPs)
2011-08-10 10:47:45 – ?  SQLServerAgent terminated (normally)
The same user that starts SQL Server(MSSQLSERVER) which works with no issue.
Fails starting SQL Server Agent (MSSQLSERVER).
All the protocols look good. Named PIPES is first.