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I am stuck with a little Oracle problem. My PC was shut down improperly after my graphics card freaked out, which caused Oracle 11g Express to not properly close down. This means that I get the above error when I try to connect. My PC has been on for 3 hours, and I still get the error, so it is safe to assume that there's something wrong.

The usual way of remedying the problem is to use the following sequence of commands from the command line:

sqlplus /nolog
SQL> connect / as sysdba
SQL> shutdown abort
SQL> startup nomount
SQL> alter database mount;
SQL> alter database open;

However, when I give the shutdown command, I get the error

ORA-12560: TNS:protocol adapter error

So now, I can't mount my db. ANy help would be appreciated.

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For your database to open and mount, first ensure that you are logged in as the user oracle Then start by checking whether your listener has been started, using the command lsnrctl status

Also, please provide the details of the environment in which you are running Oracle, i.e as an active/standby in dataguard, or standalone, and also what version of Oracle you are using. Also check your alertlog /opt/oracle/admin/databasename/bdump/alert_databasename.log if there are any clues here.

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The error you encounter can have many causes. One is an incorrect environment.

For Oracle, the variable ORACLE_HOME is very important. Start with setting that to where you installed your Oracle software. Next make sure that PATH points to %ORACLE_HOME%\bin After that, set the variable ORACLE_SID to the sid of your database instance. (The sid is part of the service name as is shown in the services control panel)

Once this is setup, you commands can be issued as you stated.

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