Picture This Theme

So I bought an uploaded “picture this” theme from here
http://www.cadengrant.me/wpthemes/?theme=PictureThis

When I uploaded it, it did not properly install and I activated it and it did not run properly.

So my question is how can I delete it completely off of my file manager and reinstall it?
I’ve deleted the files one by one off of my file manager but the folder for “picture this” is still there and continues to give me problems when I reinstall.

thanks for any help!