How can I get my photo's back into iPhoto?

My iPhoto recently crashed and lead to the computer restarting. When I rebooted my iPhoto was empty. I've tried rebuilding the library, but every time it stops at a certain number and then just carries on 'Rebuilding' whilst not actually doing anything. I looked into the iPhoto and found the master file that includes all of the photos. If all else fails I will just backup and use this file, but why is it iPhoto stops rebuilding if the photos are there? And is there a way to get the photos back into the iPhoto Library?