If you run DBCC CHECKDB and this command do not work properly then you can try third party tool to repair corrupt .mdf file. I recommend you SQL recovery software as I have also faced that type of problem. But with the help of this application I recovered entire database safe condition. So you can also use this application and save your precious data. I you have any issue regarding this recovery process you can visit this link: http://www.systoolsgroup.com/sql-recovery.html