This is a rather long addendum to, or comment on, Michael Todd's reply in response to edosoft's comment.
Rather than choosing to enable the content, check the start-up options (either (file->options->current database->display form) or (tools->start up->display form)) and remove the name of the form, having taken a note, and ensure that Allow Full Menus (same page) is ticked. You may also like to press Alt+F11 to display code, and check that for start-up code, finally, see if there is an AutoRun macro and rename it.
EDIT re Comments
You do not have to open an mdb to change the start-up form, for example, code such as this could be run from another mdb using the full name and path of the mdb you wish to change.
Sub SetStartForm(DBFile As String)
Dim prp As Object
Dim db As Database
Const PROPERTY_NOT_FOUND As Integer = 3270
Set db = OpenDatabase(DBFile)
db.Properties("StartupForm") = "(none)"
If Err.Number > 0 Then
If Err.Number = PROPERTY_NOT_FOUND Then
'' Create the new property, but this is not relevant in this case
End If
End If
db.Close
Set db = Nothing
Set prp = Nothing
End Sub