I have a 2007 mac pro that was having problems with lion osx since day one of install. I've had lion since it released. Every once in a while it would lock up on me forcing me to power down and restart. It happened again about the day before. I rebooted and the system crashed I guess cause it wouldn't boot into lion it asked me to either do a fresh install or restore from a time machine backup. I restored and everything was ok again...or so I thought. It froze the day after, I reboot but I can no longer get back into lion. It freezes during boot up and the spinning wheel just locks up. I've tried a safe boot (holding shift) and have even tried booting from my time machine backup disk to try to restore it freezes as well. I'm stuck and frustrated on this crappy OS since I no longer have any snow leopard backups.