Macbook pro only boots into safe mode, won't boot from disc.

My macbook pro (running 10.5.8) recently started freezing on a solid blue screen after the splash, on startup. It boots ok in safe mode. I've cleared the PRAM and NVRAM, and (I'm pretty sure) I've successfully disabled all of the startup items. I backed up my essentials on an external HD, and I would erase and install, but I can't get it to boot from the OS disc. It ejects it, and then goes to the blue screen. I don't live anywhere near an apple store at the moment, so any help I can get fixing it on my own would be very much appreciated!