Pictures captured by my camera are not complete

Question

While taking several perfect photos with my Canon EOS Digital Rebel, it all of a sudden began capturing only 1/2 of the photo. The display showed the bottom portion of the picture to be pure black with only a small portion of the actual picture above it. It also displays that way on the computer when I tried to see if it was just the camera display. I changed batteries, CF cards and lenses to try to solve the problem. Seems that the camera only wants to capture 1/2 of the photo. Kinda like when film is out of sinc in a film camera. Please help since I use this camera all the time.