I lost my Quicken file from twenty years ago (1997-2003)

About twenty years ago, in 2003, my Quicken file was getting too large. It had my bank accounts and credit card accounts, etc. So I did something, I forgot what Quicken called it. It created a new file starting in 2003, and kept the old data in the existing file, I think. Anyway, it is very important to me to go the very old data of important transactions I made from 1997 to 2003. I don't know how to search for these old files. I wonder what extension to look for. Maybe they are not the *.qdf extension. Maybe I had some backup files with other extensions. The computer I am using now only has qdf files from 2003 to the present, which is disappointing. I have a box of old hard drives that I will start seaching. Maybe somebody has had the same experience that I am going through and can lend me some advice. Chuck