Site crash?"White Out" and NOT recognized in dashboard!

I was installing a PDF plug in when my dashboard went white, my site went white and when I tried to log back in to dashboard to see what happened I was not recognized!!
My site adadentallab.net is still a blank white page and I had to create a new account with wp here just to ask for help.
I am NOT what you would think of as savvy re: website design. This was my first.
It has been crashed for a couple of weeks now, I was so discouraged I have taken a break. I need to get it up and running though… can anyone help?
Please spell it out though, I will not understand a thing otherwise-literally, I won’t. I seem to understand just enough to get myself into trouble!! /:( Thanks!