I'm curious, if anyone has taken apart enough failed LED light bulbs to discover if there is a trend in what part fails first. This would be interesting if it is a component that can potentially be replaced. A buck or less to get more life out of a $10 bulb seems like a good trade off!

Align the ring so that it sits flush before trying to put the screws back in. A small tab in the case needs to align with the ring correctly.

Take care that the monitor cable is tucked in when putting the bottom case back on.

No reason for this step or the next few when replacing the hard drive. Leave the DC board and its cable alone!

Press inwards between the case and the plastic around the drive. It'll flex the plastic around the drive in and away from the bottom case. The first is about an inch from the center of the slot, then centered on the slot and about one inch past the center.