[Lynne]

Using phpMyAdmin or whatever you use to access your database, run this query to close the board:

UPDATE datastore SET data = REPLACE(data, '"bbactive";i:1;', '"bbactive";i:0;') WHERE title = 'options'; 
UPDATE setting SET value=0 WHERE varname='bbactive';

If you use a table prefix, then enter that before the table name - ie. prefixdatastore and prefixsetting

Have you already contacted your host?