missing records

While adding a new record to my database I seem to have lost the majority of the previously entered records...its as if the default.dab has reverted to its first data set from several weeks ago with only 6 entries. The 200 or so CDs subsequently entered have vanished! At least I can't seem to get them to display. When I try to reenter a CD the message tells me that it is already entered. At 0.5MB default.dab appears big enough to hold 200 cds.

Any ideas about reclaiming those records?