Back in 97 there was a PC that tormented anyone that tried to fix it - would periodically fail to boot, do nothing no signs of life other than the power LED, hit reset a few times and it'd boot up like nothing was wrong and worked fine until the next time it was powered off.
Wiped/Formatted the HDD, replaced the RAM, CPU, and NIC each independently, still had the same issue. The strange thing was it never had problems when it was on the workbench, only when it was back on the desk. We'd keep 'fixing' it only to put it back and have it fail.
It lived in a computer lab so there were machines right next to it on the same power supply so we couldn't figure out any environmental causes for that specific spot.
After pouring hours of troubleshooting into that infernal machine, we eventually figured out what was different, On the workbench the machine didn't have a heavy CRT on it, back on the desk it did. Moved monitor off the top and it worked perfectly from that point on.
20 years on and I still think about that stupid machine.
