access 97

a user was using my app all day, the next day when he try to use the program
get the error like this:

the file c:\path\database.mdb not is a database valid format,

i try to read the database from msaccess app, but get the same error?

what happened, or what is wrong,,

i am frustated becuase is the second time that happen, the first tiem lose
a table, and now lose all the database.

somebody have any comments or suggestion or idea or anything, please

thanks for any idea,,,