thermistor often at offline SMPS input.....they often undersize them , and due to heating , they weaken, become too high resistance even when hot, and just fail eventually. Just replace it and see...use eye protectors. Ensure correct fuse. The MOV might have gone and that possibly blew the thermistor when it died...so replace the MOV too.....the thermistor might have actually acted as the fuse when the mov died, if the fuse say was over-rated.
Also, with any offline smps, may as well replace the big electrolytics if you want.