Is it possible she has a UTI?
I think something very subtle probably changed that might not occur to you right away. In any case, if it's not a physical problem, I would just go back to potty 101. Keep her crated for a few days, then give her access to one room, then two rooms, etc. It will probably go quickly since she knows the drill.
I agree with
westieboy about what she "knows" is wrong. Strangely enough, a dog can know that pee on the floor upsets their owner, but not associate that with the act of peeing. I don't suggest you try this,
but if YOU peed on the floor, she would probably run away from that as well.