igorsk, you are GREAT!!!
IT WORKED!!!!!!!
I'm so happy!!!
I had to re-format the internal memory after having done what you've suggested above to let the PC detect the internal memory, as the PC didn't allow me to simply delete everything which was in the internal memory.
I was afraid to re-format it, as I feared the firmware might disappear too, but this didn't happen.
Now everything is great again, I didn't have to re-format the cards, they work fine now.
THANK YOU, igorsk, you made my day!!!
Many greetings and best wishes,
Momo