no entro a oracle

[maxpower2008]

no puedo entrar a la pagina principal de oracle.
Solom puedo trabajrlo desde consola???...

Q puedo hacer intento crear conexiones con jdeveloper y me aparece este error

Test failed: Listener refused the connection with the following error:
ORA-12505, TNS:listener does not currently know of SID given in connect descriptor

Cualquier ayuda me sirve gracias.
Salu2.

[dogduck]

http://ora-12505.ora-code.com/

ORA-12505:
TNS:listener does not currently know of SID given in connect descriptor
Cause: The listener received a request to establish a connection to a database or other service. The connect descriptor received by the listener specified a SID for an instance (usually a database instance) that either has not yet dynamically registered with the listener or has not been statically configured for the listener. This may be a temporary condition such as after the listener has started, but before the database instance has registered with the listener.
Action:
- Wait a moment and try to connect a second time.

- Check which instances are currently known by the listener by executing: lsnrctl services <listener name>

- Check that the SID parameter in the connect descriptor specifies an instance known by the listener.

- Check for an event in the listener.log file.

Salu2