I have a problem with my SD Memory card?

I took pictures a few days back with my Nikon D80 camera but when I returned home and try to save the pictures in my laptop the folder (D. Stated that 'folder empty' I'm confused because when i put back the memory card inside my camera i can see all the pictures. Please help me. I really need this picture for my presentation at work

There's supposed to be a USB cord to link the camera to your computer.
If not, get one! Also, digital cameras come with a CD ROM, use this, as in some cameras it is the only way to acquire, or upload, the images from the memory card to the computer.
Note, the camera has to be switched ON prior to uploading, and remain ON for the duration of the upload.
Please remember to use the proper disconnect procedure when the uploading is complete, or you could blow your camera, and also, sometimes, the computer.
I can't detail this disconnect procedure here.
"When nothing else works, read the instructions!"

Use a USB card reader to connect your camera's memory card directly to the computer's USB slot. Upon detection, open the Computer icon (Windows My Computer) or Finder (Mac) and look for a drive labeled Removable Storage Device. Open that to see the contents of your camera's memory card. You should see everything including those that only your camera can see and hides from you.