The first thing you should do when you run into a corrupt datbase is to back up the file.
Second try and compact and repair it. It may be that some user converted the database to a later version of access than everyone is using. Old versions always report newer versions as unreadable and corrupt. Once you've determined what version the database is (and disposed of any bodies where appropriate j/k), using the appropriate version try compacting again. You can stop with this laundry list as soon as something fixed it... Make sure you are not importing hidden and system tables by making sure they are hidden (Tools Menu, Options, View Tab uncheck Hidden objects and system objects). Then try to import from a new file. If that fails try to open the file. If you can, Export tables one at a time to a new database (this is painfully slow but your grasping at the last few straws here). I'm not sure how many versions it goes through but there is an MS utility that called JetComp that allows you to compact database files. It is supposed to be able to fix some cases of database corruption that MSAccess can't. Last version I saw (I'm ramping up to move to 2000 from 97) was available in the Jet 3.5 update (I think it was SP4) for Access 97.
If that doesn't work, restore the file from backup or seek the help of professional recovery company. I've been lucky enough never to have to use one, so I can't give any strong recommendations...
I've seen advertisements for
in a good e-mail magazine I read (goto
to sign up for all kinds of Woody's magazines on MS products.) The magazines are definitely worth reading as it tells you about the problems and updates on the products. Definitely worth having it as a fixer of things that you don't use.
One more thing that you must know: If so much as one user is in the database when your backup runs, even if the backup will use a share file lock you may retore a corrupt database. This database may be repairable. You'll know you backed up a database in use if it backs up the ".ldb" file the same name as the ".mdb". And just to make things interesting, users disconnected by the network instead of closing the file normally can cause db correction. So be sure that the users know this.