The graphics card caught fire. Fortunately, I was at my desk at the time and couldn't help but notice the heavy smoke boiling out of the machine. I pulled the plug pronto which halted the fire, and put the machine out on the concrete patio till it stopped smoking. Curious, I plugged it in again and the fire started again. REmoving the cover showed the graphics card and a section of the mobo was burned to a crisp.

I had to wash the floor, walls, everything in my office to get the stink out.

Replaced the mobo and graphics card and I was back in business, but this time I bought some sheet steel and set the computer on that, which hopefully would buy some time to get the fire out.

The machine had a metal case, which I'm sure greatly slowed down the spread of the fire. So for me from now on, it's metal cases all the way, baby.

"Curious, I plugged it in again and the fire started again"

This reminds me of an old joke: https://www.reddit.com/r/ProgrammerHumor/comments/46sere/a_p...

I once turned on my crt monitor and smoke started coming out so I freaked out and immediately unplugged it. My uncle, an electronist, was passing by and told him I screwed my monitor and wanted him to take a look. He plugged in, turned it on it worked just fine. I don’t remember ever having problems with that EGA monitor again. I could never explain that white smoke

Maybe it was a literal bug.

It wouldn't be funny if it weren't true!

Computer chips work because they capture magic smoke. I know this because when I let the smoke escape the computer stops working.

I wonder if there was a tin whisker lurking there.

Wow. What model GPU/mobo was it?

I had, from what I can tell, the 3.3v power Button wire met and catch fire, no idea how and it sounds very unlikely but the computer worked once the fire was put out - I just had to start it with a screw driver.

I've seen the remains of a computer in a school, after the building was struck by lightning overnight. Only that one computer was affected, and inside it was mostly black dust.

I would guess something shorted in the power supply or power bus.