I had enough trouble with Nivo slider to convince me to try another solution, Meta Slider-lite which works fine. But even after removing Nivo and the associated media manager plug-in I still get a huge blank div id=’slider’, when I look at the source code.
In either the free version or pro, from your main admin menu, simply navigate to:
Appearance > Startup Options
Then among the checkbox options you’ll find the option to disable the slider. Additionally you may want to check under Plugins and make sure that any plugins you aren’t using are deactivating and then deleted.