So my laptop did the thing again where it suddenly shut down and refused to respond to anything afterwards.
No big deal, it's happened before. I removed the battery, put it back in, plugged the power cable into the laptop, and pressed the power button. Nothing happens.
This was concerning, obviously. It's a 1000€ laptop. Time to take it apart and see if cleaning some of the dust off would do anything. Can't quite get the top and bottom halves separated as there's a couple of cables connecting them in a hard to reach location. After trying to coax them loose with a screwdriver for a bit, I give up and reassemble the thing. One of the corners seems to resist being pushed all the way back in, preventing the screw from biting. I decide to let the corner be a bit loose and store the screw elsewhere.
And now comes the part where I look at the sockets on the wall and see that there are two things connected, neither of which are the power cable for the laptop.
I plugged both ends of the cable to their appropriate locations, and hit the power button. Laptop starts... but the monitor stays dark. ****.
After pondering with another person I was in a chat with for a bit, I decide to reopen the whole thing again.
An SD card falls from somewhere inside the laptop as I reopen it, explaining the trouble with the corner. And indeed, it turns out that one of the cables I tried to coax loose - specifically the one that connects to the GPU - did get unplugged. It's a bit hard to reach, but I eventually manage to get it back in place and the laptop reassembled.
I hit the power button, and after two and a half hours of struggling, it boots just fine.
Lessons were learned today.