Well, if you have full access to the database host you don't need to delete and re-create the password file.
According to Using Operating System Authentication section in Database Administrator's Guide logging in as an OS user which is a member of
dba group on *nix or
ora_dba group on Windows and connecting to an Oracle Database instance using SQL*Plus with
SYSOPERprivileges should do the trick.
$ ssh root@orcldbxe1
[root@orcldbxe1 ~]# su - oracle
[oracle@orcldbxe1 ~]$ groups
oinstall wheel dba
[oracle@orcldbxe1 ~]$ sqlplus / as sysdba
SQL*Plus: Release 126.96.36.199.0 Production on Fri Aug 22 08:22:35 2014
Copyright (c) 1982, 2011, Oracle. All rights reserved.
Oracle Database 11g Express Edition Release 188.8.131.52.0 - 64bit Production
SQL> select status from v$instance;
That's why it's called operating system authentication – you use operating system group. Simple and convenient, and no need to remember passwords. I always use it.
Once you're in, you can reset passwords and do other administrative tasks.
SQL> alter user spongebob identified by s3cr3t;