Memory card won't work in my Camera?

I've got a slight problem here.
I'm using SanDisk Ultra II SD HC 4 GB memory card and it worked brilliant before. Then, on one lovely day I used the card for music (MP3) files and in my FM transmitter. Unfortunately after that my camera (Nikon D80) refused to recognize the card altough it works perfectly in my laptop and in my FM transmitter: S so I'm a bit confused. I can't "Format memory card" in my camera because it doesn't recognize it! So please. If you can… Help ME!

Evidently it doesn't like the current format.

The best thing to do is go buy a new memory card strictly for your camera. BestBuy caries 4GB SDHC high speed cards for $11.99 to $19.99 (and you could probably find them cheaper elsewhere).

People just don't understand these cards and you appear to be one of them.

These cards are designed to be specific to one device.So, once formatted in a particular camera use it only for that camera. These things are so inexpensive now that trying to use for multi purposes makes no sense economically and technically - they don't work that way.

If you have say 5 devices that take memory cards then you should have at least 5 cards, one for each device and then use that particular card only for that particular device.