Won't boot. Keyboard light on. No screen. SF314-512-52MZ

This problem just began today. After powering on, I get keyboard light, but no screen and no other signs of life.

I researched and found some advice to use the battery reset button on the back. The machine will attempt to boot after holding the battery reset button, but after about 30 seconds, the screen glitches and then goes black (but still backlit). I got exactly the same behavior when I booted into the BIOS menu. I was going to disable fast boot, but before I saved and exited, the screen went black and the fans started running at about half speed.

If this happens even in BIOS, I guess it must be hardware?