Can not open database file

Hi, all

We have a database which was running on the server and used by several
users. We can not the database now with the following message:

The "*.mdb" need to be repaired or isn't a database file.
You or another user may have unexpectedly quit Microsoft Access while
the Access database was open.

I tried to compact and repair, but it was failed. I tried to open a new
blank database file and import the bad database file, it was failed
too.

Please give me some suggestions!

Thanks a lot for the help!

.