How to connect to newly installed Oracle XE instance?

Question

I have installed Oracle XE on Win7 x64 machine. Installation completed successfully without problem, or perhaps installer didn't tell about them. But after installation I can't connect to database; its web interface is not working. I have looked through list of open ports, and there is no 8080 port as was noted during installation. Also I can't connect via SQLPlus.

SQL> connect SYSTEM
Enter password:
ERROR:
ORA-12638: Credential retrieval failed

Somewhere in the web it was told to edit sqlnet.ora file, I have changed it in the following way:

# SQLNET.AUTHENTICATION_SERVICES = (NTS)
SQLNET.AUTHENTICATION_SERVICES = (NONE)

and now I get next error

SQL> connect SYSTEM
Enter password:
ERROR:
ORA-01034: ORACLE not available
ORA-27101: shared memory realm does not exist

What do I need to change so that I can connect to it?

Answer 1

I figured out the issue.
I was using domain login to install Oracle XE. If you are using domain login to install Oracle XE then the database creation will fail (though you may not get any error messages on that regard).
Solution:
Install Oracle using a local admin user.
Change SQLNET.AUTHENTICATION_SERVICES to (NONE) in sqlnet.ora.
Now login with your domain user to use oracle XE.

Answer 2

Check the Oracle services are started

Answer 3

Did you set your ORACLE_SID environment variable to the name of the instance you're connecting to?