Are my files lost or can I retrieve them?

My family has a Compaq Presario 5000 which has Windows XP on a 20GB hard drive. This hard drive has 2 versions of XP. One is missing hal.dll and the other is the one my family had been using for the longest time. This computer hasn’t been used since 2007. In 2014, I got the computer out of storage and I got into XP.I think I force shut it down so many times that now it won’t boot so I put it away for awhile. 5 years later, I had plugged it into my IDE port old Dell XPS 630i with Windows 7. I was able to go to file explorer on Windows 7 and I did see the 20GB drive called “Compaq”. All the files were there and my plan was to copy all the files over the next day. When I started it I saw that Windows 7 was trying to check the drive for errors with chkdsk so I thought “hey maybe if I let this run, it will make Windows XP work on the old Compaq.” So I let it run and I got multiple lines of “file record segment XXXX is unreadable” so that scared me a little bit and I told myself that the next time this boots up, I’m going to put everything to a flash drive before I screw something up. The chkdsk has finished and I booted up into Windows 7. From there I went to file explorer and all of it was gone. Drive letter F was completely empty and I got an error message saying “the drive is inaccessible due to different format”. I restarted the computer In hope that they would show back up and the chkdsk scan popped up again but it showed “Compaq” so it recognizes that Compaq does exist.