The only way to change back to original settings is to use system restore points,
I have found that if you have a saved theme, every time you change a setting windows add an un-saved theme,
So if you right click your desktop and click on personalize,
Look at how many of these are listed in the (my themes) top listing,
Also if this does not seem to be changing when you have a saved named theme,
Look on the top left and click on change desktop icons,
Check the box, allow themes to change desktop icons,
But this also requires that you start with a saved theme with all of your settings the way you like them,
It has saved me allot of time and remembering to make system restore points before experimenting with settings,
Every time I change a setting windows adds a unsaved theme in the my themes listing.