I've been having an issue lately where the mouse clicks UNDER where I intend to. It's very annoying, and windows mouse settings do not have a "reset to default" button.
So I went looking, found a regedit FAQ on mouse settings, where it gave me a field of defaults. I punched them all in and exited regedit.
When I went to close the tab, I noticed that the FAQ I had just followed was for WIN98.
Either way, mouse feels pretty snappy now.
