2 days after I installed El Capitan, I was at a web page with a video and was getting to watch the speech when the screen turned white and the Mac rebooted.
During the reboot, the screen turned into a White+Pink vertical zebra stripes and fsck froze after a while and did not progress.
Rebooted from cold again and it did the same thing.
Rebooted while pressing D key. Did Apple Hardware Test and extended tests. Nothing bad showed up and the screen is still with White+Pink stripes.
Was there a video driver change in El Capitan that was not compatible or something?