Basically, when I installed Leopard it corrupted all of my privileges. On pretty much everything a user named "_unknown" had Read & Write privileges and my user name did not show up at all. So... I tried to fix it myself. I opened the Get Info screen for my main OS X partition and removed the "_unknown" and added Read & Write permissions for my user name, and then checked off "Apply to enclosed items" so it would apply to everything on the disk. It was taking a while so I went and got an overdue oil change for my car. When I came back it was done, but the computer was running kind of sluggishly. I opened the dashboard and looked at iStat Pro to see what applications were running, and there were quite a few that I didn't recognize the names of. I didn't write down what any of them were. They were all taking up a very tiny amount of system resources each. I decided to reboot to see if that would help. ...And now I can't start OS X. It gets to the grey Apple logo and the spinning circle underneath it and just sits there. I can boot into the Windows partition (how I'm posting this now), but I can't get into OS X at all. Please help me out. What can I do?