Whats up with my memory card?

Download http://www.recuva.com/ it's a free photo recovery software. Do a deep scan to try to retrieve the pics.

If you don't want or need the pics on your card, then format the card.

Or, run down to walmart and buy an extra card.

And HAPPY BIRTHDAY.

Have you tried popping the SD card into the computer to see if it can read/see them? Put it in, go to "my computer", open it op, and check to see if it sees your pictures. If it does then you can pretty much safely assume that the card reader in your camera is going bad or already has, and in that case you'd need a new camera. If your computer doesn't see them then it's most likely the card itself, and in that case you might have actually lost your pictures.

For the "space" problem, assuming the computer can read the card, you can save those pictures onto the computer, (IE click and drag into a new folder). Don't "copy" them as that will not remove them from card, but rather just move them. But first, you need to make sure that either the card or the card reader on camera is working.

This sounds like you've been moving pictures backward and forward between the camera and the memory card. See if you can browse your photos by connecting the camera to a computer or by putting the memory card into a computer. If you can, move them all off the card onto your computer and then format the memory card. In future don't move file back and forth, just move and delete them from the memory card.