Checked is accelerated or with precision, and unchecked is what you're looking for. Hope that helps
Sorry, no. Unfortunately unless it is either adjusted to be a straight curve (a la Cheesemfix or CPL mouse fix), or it is removed from the kernel, that option does not work entirely. This is because in many situations (especially gaming) the options turns back on.
If anyone finds a fix to remove it from the OS/Kernel entirely, please post it. The old method that I knew of was this:
However it does not work for W7 due to changes in OS.