Don't overwrite your latest backup.
Make a new copy of your your latest 3 backup (*.mbf) onto other media. Also copy your *.mny file to other media before proceeding.
Try Quick and Standard file repair.
If you still have a problem, File->Restore your backup.
If the backup has a problem,
o See if you can open Sample.mny from your Money installation folder
o If Sample.mny won't open, install the version of Microsoft Money appropriate to your region using what is currently the second thread on this forum. If that is Money Plus Deluxe Sunset, also apply the patch discussed in the first post.
o review your backup procedures for the future.
o In View, sort the registers by order of entry,
and delete the new ones.