Can't open error

Hey all,

I enjoy been using calibre for awhile without issue and then a few days ago I got the following error message after starting it up.

Picture of error message is attached. I can't do anything. Can't edit, delete books, add books nothing other than see the list of books.

I've tried:
repairing the program option when installing Calibre
Checking database
Restore database.
And other things I can't recall.

Each one failed to fix the problem and the database couldn't be restore.

Any ideas? Thanks

Attached Thumbnails