I tried installing the update today. During the installation it stalled and hung at "moving items into place". After a couple hours, I forcibly shut down the computer. Now it will not boot. I can get into the gray screen but it hangs there and wont progress. I have tried booting into safe mode (holding shift). The loading bar comes up, it makes it about a quarter of the way and reverts to no loading bar and a spinning indicator. Before I reformat and reinstall, is there anything I can try? I have a SL partition on the same disk, so I have access to the lion disk. And before anyone asks, I do have a backup, its not a huge deal to reinstall, it would just be simpler to fix it.