I had my HD fail so I went to best buy and bought a new one and installed it. I then installed leopard and it worked. I then went to restore the drive using disk utility of boot DVD and it it said successful time machine restore. Once restarted i get a grey screen right after the apple that says you must reboot with the power button? Any ideas. I can see the drive disk utility (from the install dvd) and it appears to be fine. Did a pram reset.