I have been using In House Accountant since 1989, it is a basic ACCOUNTING program that I know inside and out. I am willing to PAY the first person who can help me undo something I did to reverse over 3000 transactions when I flipped my year end and forgot to back up the last year.  I can give further details if anyone thinks they can help.  IHA is out of business and I have tried everything I know.  I do not know how to GO into the program to undo the year end and go back to a few days earlier when all my transactions were visible.  All I have now is totals.  I am freaking out.
I will pay this reward when this is done,  Please help meI don't have a solution. But a warning. The more you do to fix the problem, the worse it will become.
You need to find a wanton make a forensic copy of h your hard drive.  WAIT, better let someone else do that.
If thins is really important to you, you may have to employ a data recovery service to find files that were marked for erasure.
What they change is hard to say. Ask among your contacts for a service that know of in your  area. Otherwise, you need to contact a expert service and ship the drive per their instructions.

Start with Seagate. They offer data recovery. For a price. Or choose another if you are confident they are reliable. You may nobly GET one shot a t getting back your data.

https://services.seagate.com/
I do not work for Seagate, in case you wonder.thank you