Oracle Database Throws ORA-01092 after Patching

[Pepa]

I applied patch set 10.0.2.0.4 and then cycled my server. Now when I try to bring up my database, I get the following:

SQL> startup;
ORACLE instance started.

Total System Global Area 3942645760 bytes
Fixed Size 2070544 bytes
Variable Size 1979713520 bytes
Database Buffers 1946157056 bytes
Redo Buffers 14704640 bytes
Database mounted.
ORA-01092: ORACLE instance terminated. Disconnection force

SQL> startup;
ORA-24324: service handle not initialized
ORA-01041: internal error. hostdef extension doesn't exist
SQL>

Can anyone help me?

[Golfi]

Look at alert_sid.log file,

I betcha that you will quickly comprehend that your database has not been upgraded. You only upgraded your binary files.

Read the upgrade guide again and upgrade the database.