Answer by  
                                                                                          AnilaDS (23)
                                                            
                          
                          
                                                          1. Login to SQL plus
 -sqlplus/nolog
 -connect/as sysdba
 2. The db must be mounted exclusively and not open for operation
 -startup mount;
 3.Check the log mode status of the data base
 -select log_mode from v$database;
 4. Setting it to noarchivelog mode
 -alter database noarchivelog;