check trace and log files (under %oraclehome%\rdbms73(?)\trace and log I believe).
Try to start database with svrmgr(73 may be svrmgr30 or 23, check in bin\) and see logs/trace for errors.
To start DB with svrmgrl:
set ORACLE_SID=<your sid>
svrmgr30
connect internal/oracle(or other password, default is oracle)
startup
Other 'low level' commands in execution order:
startup nomount
alter database mount
alter database open
and see what is going on. May be have to reinstall oracle binaries, configure registry, fix OS or hardware...
Yes, Oracle Services must be running (oradim has to be used), as well as account for those services must have all necessary rights - usually has.
What else makes sense to setup/check are:
oracle_sid in NT registry
NLS_LANG to american_america.... both in registry and in create database.
path to oracle_home\bin is good thing, but not very critical(?)
oracle.key in bin: THAT ONE IS CRITICAL, if exists in 7.3. Check and set its contents to correct oracle home.
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