connect / as sysdba ora-01031 insufficient privileges

If your system under domain environment and if you want to add your domain user into ora_dba group.

Use oracle managed objects console and add your user.

How to tell if the database was started with spfile or pfile?

http://oraclespin.wordpress.com/2008/06/22/how-to-tell-if-the-database-was-started-with-spfile-or-pfile/