Before doing anything else, make a copy of your database.
First make sure that your installation of Windows and Office is fully up to date.
Try importing everything to a new, blank database. To do that, create a new database, then use the External Data ribbon item, select Access, then select the trouble db and try to import everything to the new one.
If that doesn't work, you might try a compact operation, but if you can't open the database you may have troubles with that. You can compact from another database via code:
DBEngine.CompactDatabase "full path to the trouble db", "Full path to a different db"
Note the second db (the "full path to a different db") does not need to exist.
If that doesn't work, you might need to enlist the aid of a 3rd party to help. Access Recovery Toolbox at
http://www.oemailrecovery.com/access_recovery.html does a very good job of recovering Access databases.