As a 12 year old: I tried to overclock my first "good" own computer (AMD Duron 1200 MHz). System wouldn't start at 1600 MHz and I didn't know BIOS reset exists.
I ended up putting the computer in the freezer and let it cool down for an hour. I placed the CRT display on top and the power/VGA keyboard cable going into the freezer. I managed to set it back to the original frequency before it died.