This is how to disable archiving:
C:> sqlplus sys/@dbalias as sysdba
SQL> shutdown immediate
SQL> startup mount
SQL> alter database noarchivelog;
SQL> alter database open;
SQL> archive log list
SQL> alter system switch logfile;
Run this about 10 times, delete all archived log files and then proceed.
This is how to enable archiving:
SQL> archive log list
At this point the numbers should have incremented as many as the number of switches.
SQL> shutdown immediate
SQL> startup mount
SQL> alter database archivelog;
Database altered.
SQL> alter database open;
SQL> archive log list
SQL> alter system switch logfile;
Run this a couple of times and you should see new archived log files.
SQL> archive log list
At this point the numbers should have incremented as many as the number of switches.
Exit SQLPlus and do an immediate full backup of the system.