You will need a card reader on your computer for the memory card.
And you will need some file recovery software.
There are hundreds of file recovery software programs available.
All require you to buy the software before you can recover the files.
Do a Google search for:
memory card file recovery
I only know of one such program that is free:
Several people report that they had good results with it.
I bought a new memory card and forgot to format it when I loaded it into my camera - a canon eos. It took about 100 photos before I got an error message and cannot create folder message. When i tried to download photos onto my computer, I received a message there there were no images yet I previewed many images and they were there at one time. Thanks for any advice you can give me.