I have a Macbook. I broke my HDD several months back (it was 10.6.x) and replaced it with my brother's old HDD (10.5.8). From then on when I turned it on, it would chime, and go to a black screen. On the black screen it would show what it was doing. (I.E - Turned Airport on, No ethernet connected, turned on the processor, et cetera). I just got Snow Leopard again, I was lazy, and when I install it runs fine until the restart. It says "45 Minutes Left" and "Upgrade will resume on restart." It goes to restart the Mac, comes to the black screen start up, turns everything on, and does not continue the upgrade. Does anyone have any ideas or solutions? Thank you.