Change Log for custom tables

Hello Experts,

   I have a custom table that has 10 fields and this table is being updated with several custom programs. Any time a program updates the table only the last change to the record is saved, but the previous changes are not logged anywhere in the system. But now i want to find out all the changes that happened on a specific record. Can someone point me a proper way to find this.

Thanks for your time.

Regards

Amit.