I've been having the same problem with mine. I also replaced the disk drive. I find that if I try to boot it over and over, after 30 or 40 times, it will catch. It's a real PITA. I went to leaving the machine on and booted once I got it to catch, but then had to replace a burned out power supply, so I guess that's not a fix either. I'll be watching this post to see if anyone has any ideas. I sure would like to have it like it used to be, there when I needed it without having to fight with getting it to boot.