ultra sandisk 4gb Formatting

Is it necessary to format the disk before taking any pictures if so how do you do this i am really a beginner at this and put a new 4gb card in my camera and now when i go to download to my computer it reads error .I even tried downloading thru my hp photosmart and it reads error also…guess i really goofed. 

i can see the pics on my camera but need to download to forward    any help would be appreciated :cry:

Usually your camera will tell you if it needs to format the memory card, and will do it for you. Of course, if you have already snapped & stored any pictures these will be erased during the format procedure.