Oracledbconsole service not starting

I have installed HP's Service desk 5.1 software on a Windows 2003 Server with Oracle 10g as backend database. Everything ran fine for one day but now the Oracle database will not start. The HP Service Desk console will not log in. The OracleDBConsole service will not start and I get the error "The OracleDBConsole service terminated with service-specific error 2. I have added OC4J_DBConsole_localhost_orcl as suggessted in other post with no luck. I also get the errors ORA-01034 Oracle not available and Oracle-27101 shared memory realm does not exist when trying to log in to SQL/Plus. I believe the service desk problems all stem from the database not starting.

I gather that you are running the database server on Windows.
Have you had a look in the alert log for any errors about why teh service is failing and have hou looked in the Event viewer for any errors for oracle there may be more information there
Do the following and see if you can start your instance manually

Log in as an administrator to the Server(ideally the one you installed the database with
Start a dos prompt set your ORACLE_HOME and ORACLE_SID environment parameters.
connect to the database sqlplus / as sysdba
startup

Did the service have the user name or password changed after installation. Chck what the suer is that is running the service. You may have to grant it rights like log on as a service