Tiger,
Your reaction was heated and antagonistic, thus what do you expect in return? Flowers and apology because you obviously haven't a clue to how complex the problems with PC enviroment can be. It is a level of deduction, the steps I provided were logical, used before, and from many years of experiance, certification, and knowing WHAT THE HELL I WAS DOING.
Take the advise or not, the steps are the steps to point out ONE part is function, or ONE part is NOT functioning. There is a limited set of parts, it is a step by step process, and your 'reasoning' of 'just knowing' doesn't prove a thing. That is why I laid it out to prove to yourself, which part is the problem because your reasoning makes NO SENSE. There is no magical Windows changes your setting just because your in a game only on the mouse. THE ONLY advertised item that does that 'description' is Mouse Applications, that would provide for example Mouse button combos for EVE flying as compared to BF4 Medic class soldier, or lower DPI in using Paint Shop Pro but for Ghosts would ramp it to 3200DPI.
You refuse to believe the software could possible be involved. That leave that Windows is screwed up in the registery, which means a reload. SO to prove what IS the cause, there is the steps. One STEP at a time. You do them and then observe, you see a change then you NARROWED it to the specifics that changed and you know where it is that causes it. SIMPLE. But for you complex. Sorry, but that is either whining for the sake of whining or your just better to not waste more effort on a PC when a console is more your speed. It is no big deal, I can't for shit play console with those joysticks, I admit it freely. Is no big deal, your the only one being rude, crude and obnoxious, and most of all childish on the matter.
Take the advise, leave it, take the PC to a Professional IT tech, or just unplug it and leave it in the corner. Doesnt' matter to me, my life moves on. But ask a simple question... WHAT IF I AM RIGHT?