Camera won't take photos

I connected my Nikon D40X to my computer earlier today to upload some pictures. I thought I had "ejected" the camera from the computer before I turned it off but I had forgotten to "eject" it & got the standard warning message on the computer, saying the camera had been incorrectly disconnected. I unplugged the camera & didn't use it for a few hours. Now that I am trying to take photos, it won't. When I hold down the shutter, it only makes a series of quick, quiet clicks & won't focus or actually take the photo. I tried resetting the camera but it didn't have any effect. HALP!