Exchange 2010 Database Dismounted, Corrupted

Check if your .edb files are not locked by your local antivirus (btw that can also be the cause of the corruption)

I found also move the file to a different hardrive in case the corruption is hardware related.

You look here: http://forums.msexchange.org/m_1800600673/mpage_1/key_/tm.htm#1800600673

This is what worked for me when I had RAID issues that corrupted my Exchange database.

1. Check your storage. (By "storage," I mean your hard drive or RAID array.) Correct any errors here.
2. Run Eseutil /P.
3. After Eseutil /P runs successfully, run Eseutil /D.
4. After Eseutil /D runs successfully, run Isinteg -fix -test alltests.

However, Microsoft itself says that the above procedure is a "last resort" and can result in data loss. Also, be aware that the above procedure requires a lot of time and disk space (more than twice the size of the database). So, you know. If restoring from backup is an option, you probably want to go that route instead.

And if restoring from backup isn't an option? Honestly, I think it's time to pull out the credit card and call Microsoft.