ORA-1113 signalled during: alter database open

The ORa-1113 error means that your Backup implementation does an ALTER TABLESPACE BEGIN BACKUP and END BACKUP for each tablespace.

 Start the service.

Go to Windows command line prompt as the Administrator or account in the OS_DBA group (with the right ORACLE_SID, ORACLE_HOME and PATH)

sqlplus / as sysdba

startup mount -- or ALTER DATABASE MOUNT if it did get started but not mounted

ALTER TABLESPACE (tablespacename_that_was_in_backup_mode) END BACKUP ;
(if there were multiple tablespaces in backup mode, issue the END BACKUP for each one of them)

ALTER DATABASE OPEN ;
The other option to step 5 is the "RECOVER DATABASE" . Oracle may apply archivelogs to synchronise the datafiles back.