I'm on app which called SQL Server 2008. I have been hardly working with it during some years. Some time ago, bad thing happened – I made an effort of opening .mdf and I couldn’t, SQL Server even neither open nor gives messages.
How did you try to open the MDF ?
Copy the MDF and LDF files (so you have a backup)
Then try to ATTACH the Database (both MDF and LDF if you have both, otherwise just the MDF)
If you have a BACKUP file then restore that