New theory. I think my laptop may have an issue with the hinge, where the detection is messed up so it thinks it's sleeping when I power it on and thus never goes anywhere. It seems like extending the screen all the way back is a surefire way to get it to turn on.

Also I unplugged and replugged everything I could on the mobo and one of the RAM sticks wasn't detected after I booted again. That's just grand. 8gb ram life bois.