recovery of docs and images from external HD

[bootsboots]

I got the error message that my external HD was "corrupt and unreadable." I googled how to fix this, but nothing I tried worked. One suggestion was to use Recuva, so I downloaded the free program. It has been almost 24 hours now, and it says it is still in part 1, and the numer of ddays left keeps changing very nanosecond from 6 hours to 43 days, and everything in between. It is a 1 TB HD, about 50% full. It also displays thet it is 5482% scanned. This all seems very strange to me, but I am 71 years old and know next to nothing about computers. I am desperate to recover these files and images. Any thoughts?