Files download and browser goes nowhere

I’m a layperson with no coding experience. Yesterday, I logged in to my website through my WordPress account and deleted a few pages and posts. I also updated plug-ins. I don’t think I did anything else out too out of my “element” but now when I type my domain into my browser, a file downloads to my computer and my browser goes nowhere. The Bluehost chat representative said the problem was my Cornerstone plugin. How do I get help fixing it?