ORA-01034: ORACLE not available for Oracle 10g

ORA-01034: ORACLE not available for Oracle 10g
Cause : Oracle Failed to initiate startup on windows 2003

Answer :
- Check all initiate variable is correct especially ORACLE SID
- simple restart might do
- try to clean windows event viewer from computer management
- startup manual
1. start sqlplus/nolog
2. connect system/password as sysdba
3. shutdown/startup