I love these debug stories. My interesting one was from a job repairing computers in high school. My older colleague was upgrading a 486, and couldn't get the

I love these debug stories. My interesting one was from a job repairing computers in high school. My older colleague was upgrading a 486, and couldn't get the system to boot on the first try, but if you hit the reset button after it was already on then it would boot just fine. All the hardware tested fine in other systems. I figured out the problem by listening to the hard drive. I could tell it wasn't spinning at full speed when it was initially booting. The system would get through the POST process before the hard drive could finish spinning up. So the initial boot from power-off would fail. The solution ended up being to upgrade the hard drive (or downgrade the motherboard).