MacBook stuck in OS X installer

I have been trying to install 10.5 from 2 disks I received from Apple, everything seems good until the first disk gets ejected and I put in the 2nd of two. It doesn't do anything, its stays on the blue installer screen and nothing happens. I'm not sure what to do from here? Someone said the 2nd disk is the application disk, but they both say install disk. help?