Thanks Sarge for having taken the time to write me so complete an answer.
Concerning Quicktime, I've got the player and it works with other stuff. But with Meat's vids, I've got first a white screeen with the blue drawing at the middle (just as if it was uploading) for a few seconds and then it turned into a little icon picturing the blue thing broken.
I've got Windows and Real media players but I guess my problem comes from my computer which is both too full and too old and therefore I can't upload the latest versions of the players. My Windows version is just out of date, I'd be ashamed to name it
Too bad for me...
Thanks again for having tried to help me.
Florence