I'm current running 10.4.11 on a 2.2 GHz MBP with 2 GB of Ram. I wanted to update to Snow Leopard but, when I load the disc and launch the installer, it asks to restart the computer. When it does, it spins up and then ejects and my 10.4.11 system is launched. I thought this was compatible but confused as to why it's not working. Holding down "C" while booting isn't working either. Any suggestions? Thanks.