Ever since I got Lion, my almost one year old, mid-2010 MacBook Pro could easily be mistaken for one from five years ago (minus its design). Kernel panics became a daily event, HDMI and other external devices don't always work, Time Machine backups take hours (not just the first after upgrading), etc. So what I wanted to do is downgrade back to Snow Leopard. I've tried multiple methods (format then reinstall from OS install DVD, partition and install, etc) but it seems there is a common problem: after moving my files over, I can't access Snow Leopard unless in safe mode. After the boot sequence, when I get to the part where I would normally have my log in screen, it goes to a bright blue screen and sticks there. My guess is it's caused by some system files/drivers etc., but I'm not sure how to not include those. So what I'm asking is either (a) How can I not include system files in Time Machine backups, or (b) How can I not move those over while moving everything else (Users, Applications etc) from Migration Assistant? Thanks for any help.