I've been trying to do a factory reset on my Galaxy S5, but every time I click reset, it pops up saying settings has stopped working, and will not continue. I've tried restarting, and it does the same thing. What can I do now?
It sounds as if the ROM is corrupted, and you'll have to reflash it. See [Samsung] How to flash Stock ROM via ODIN. (No need to warn you about losing data, you would anyway by resetting.)