To start with, in a few words you should explain who you are.
I do not know the 350D but in the menu there should be a picto (spanner and hammer) and somewhere in the list you will see "Firmware Ver xxxxx)
Check if you can read your CF card from your PC (card reader)
Check if you can connect your 350D to your PC (USB cable and EOS Utility)
Try to format your CF card
Try another CF card


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Tout d'abord un petit passage vers la case présentation serait sympathique.