ambiobloodlegion on "Theme Help Please"

I edited one of the CSS themes and now my blog will not reset.
When I activate a new theme it will not change to the theme that I activate.
As you can see I am using the Theme: Motion by 85ideas. But my blog is not displaying it at all.
Can someone please direct me as to how to reset this completely? I tries deleteing all the CSS and saving from scratch but that did not work. I opened another one of my blogs and copied the theme's CSS and pasted it and that did not work either.