Iphoto not responding - Missing photos

Hello I have a macbook and was importing some photos vis CD, the Macbook then ran out of power. I restarted the macbook and Iphoto was not responding and I had to force shutdown. Iphoto nows says not responding. I started Iphoto with the Alt key and chose library but none of my old pics are there? 1000s of photos gone. Please can anyone help? Are the photos still there somewhere?