I'm running Leopard 10.5.8 on an iMac and continuously have problems booting the machine. The boot process occasionally hangs at the gray screen, but more often it hangs at the blue screen. Sometimes it makes it to the login screen where the cursor occasionally freezes. Whenever these problems occur I have to shut down by holding down the start button, then restart again. Usually the second boot is successful. This booting problem occurs frequently, even after running Disk Warrior and repairing permissions. I don't think this is normal behavior. Has anyone else had such problems? Is there anything I can do to correct this behavior, or is this something that needs to be fixed by Apple? Thanks for your help.