Aperture causes my MBP to hang.

Aperture causes my MBP to hang. Upon opening Aperture it says it is attempting to open library and I get the spinning beach ball if I try to do anything else, even trying to force quit Aperture. Than the entore computer freezes and a power down cycle is the only thing I can do to get my MBP to work. I've moved some of the jpgs from my original destination to another external hard drive. This may be the cause. Is there any way to save my Aperture library without losing all my pictures?