No criticism of your English here, it's way better than my less than schoolboy French, but can I try to confirm a couple of things, as I find I'm able to read your post in 2 different ways?
You have a 2GB SD card which was OK when inside your Panasonic. You actually checked the pictures before you took it out of the camera, and when inserted into the card reader you get nothing, and no software will read it. That's one way I've read it.
The other way I'm reading it.
Same 2GB SD card which you formatted inside your Panasonic, and now you're having problems getting XP or Win7 to read that card, although you have successfully formatted other cards in that camera with no problems.
If it would help, we do have a French speaking member, Aethec, who would be able to translate a post you made in your native language if that would be easier for you to explain exactly what the issue is, as I'm slightly confused.
You could post your reply in English and French if you wish.
I'm not saying Aethec or any of the other guys, including myself, will have an answer to your problem, but he will be able to fully understand you.
Apologies for the confusion, although the guys will probably tell you I'm often confused.