How Do You Put Videos To Your Computer From Digital Camera?

How do you put videos to your computer from digital camera?
i have a canon power shot sd880IS and was wondering how you transfer the videos from the camera. the memory card already has pics in it and i made a cuple vid. but when i hook it up to the computer..it doesnt show the video but pics only…HELP!!! also when i put the sd card in the memory reader…nothing comes up.