i agree negative doesn't work, it's all about praise. watch her closely and when she starts sniffing around or eyeing one of her usual spots, grab her gently and put her in the litter box. even if all she does is stand there or sniff around, pet her and tell her what a good kitty she is. any and every time you see her use the box or even go to investigate it, praise her. act like her bodily functions are the most amazing thing you've ever seen
if it keeps up most definately take her to the vet, to rule out an infection or worms or a blockage etc.
what litter do you use? if it's a clay-based litter, especially clumping, i recommend switching to one like yesterday's news which is pellets of recycled newspaper. clay-based litters are actually known to cause respiratory infections and bowel obstructions in young cats and respiratory problems and allergies in people. and the newspaper stuff is dirt cheap. my cat adjusted to it without any problems, i had to switch after he got an upper respiratory infection that wouldn't go away, i put 2 and 2 together after i saw him coughing in his box right after i'd poured in clean litter.
also where is the litter box and what is near it? when had several camping/biking trips in the summer we were in the habit of dumping all the gear on the basement floor til the next weekend, within easy reach, but the cat decided it was too close to his potty space and peed all over all our gear. didn't take long to figure out he was ticked off at the stuff being in his path from the stairs to the box. or else ticked at us for leaving him alone and associated the camping gear with us leaving for 2 days at a time
basically make sure the box is in a clean, uncluttered and quiet space and not in a major traffic area. some cats are modest and don't like peeing where people are constantly walking by. or if the box is too close to the food dish. that's a turn off.
just some ideas, hope you sort it out before the move but try to be patient with her, she's doing it for a reason