Error Starting Up Database in Oracle 10g
 

I have Oracle 10g running on my Fedora system. Its been working fine for about a month but now my database will not startup. When I run:
sqlplus /nolog
connect as system/password as sysdba
startup

I get the following:

Total System Global Area 188743680 bytes
Fixed Size 778036 bytes
Variable Size 162537676 bytes
Database Buffers 25165824 bytes
Redo Buffers 262144 bytes
Database mounted.
ORA-01092: ORACLE instance terminated. Disconnection forced

It looks like its starting up but then terminates. Anyone run into this before? Usually all I have to do to start my database is run dbstart. Now when I run dbstart nothing happens. My listener still starts up fine though.