W8.1. Vertical scroll with an MS 5000 wireless mouse is fine for weeks, then suddenly it's on steroids.\ Changing it in Mouse PROPERTIES (or the registry) returns speed to normal, but only until the next boot, when it reverts to fast. Reinstalling MS Mouse and Keyboard Center software is a fix - for a time. Then the scenario is repeated. Clues as to why the setting doesn't "stick?"