I tried logging onto my database through sqlplus and got the following error
ORA-01092: Oracle instance terminated. Disconnecttion forced

I tried to connect as internal through SQLPLUS and received the below error message:

ORA-24327: need explicit attach before authenticating a user

I therefore went to the dos prompt to connect to server manager to get it started but it did not. Below is what I did:

PL/SQL Release 8.1.5.0.0 - Production

SVRMGR> connect internal/oracle
Connected.
SVRMGR> startup
ORA-01081: cannot start already-running ORACLE - shut it down first
SVRMGR> shutdown
ORA-03114: not connected to ORACLE
SVRMGR> startup
ORA-01031: insufficient privileges
SVRMGR> connect internal
Connected.
SVRMGR> startup
ORA-01081: cannot start already-running ORACLE - shut it down first
SVRMGR> connect internal
Connected.
SVRMGR> shutdown
ORA-03114: not connected to ORACLE
SVRMGR> connect internal
Connected.
SVRMGR> select * from v$database;
select * from v$database
*
ORA-03114: not connected to ORACLE
SVRMGR>
SVRMGR> startup
ORA-01031: insufficient privileges
SVRMGR> connect internal
Password:
Connected.
SVRMGR>
SVRMGR> startup
ORA-01081: cannot start already-running ORACLE - shut it down first
SVRMGR> connect internal/oracle
Connected.
SVRMGR> startup
ORA-01081: cannot start already-running ORACLE - shut it down first


NOTE:
I'm running small databases on this machine.
O/S= WINDOWS 98
ORACLE VERSION=8.1.5.0.0. Enterprise edition