Sd card problems

[Guest]

I just took wonderful pictures of my kids 1gb took all day at beach, just looked at on camera took sd card out put in my laptop and it says i need to format to use card- what does this mean?? Please someone tell me I didn't loose 300 pic's that I took today-

 

[techie555]

Maybe the SD card is already full.
Can you connect your camera (with SD card inside) on your laptop via USB?