you are not playing around with settings because there is no way back at this point. Same here!
That's not entirely accurate. If you keep a log of what the default was for
a setting before you changed it, you can always revert to the original by
manually changing it back. Inconvenient, but certainly possible. I always
take this approach when changing BIOS settings as well - and have a hard
copy handy, not just a machine-readable file.
Of course, uninstalling and reinstalling is a sure-fire way to make a global reset.