Good evening Mark and welcome to the Events Calendar Support forum!
Thank you for reaching out to us.
We are sorry to hear about the admin area being wonky.
I would love to help you with this topic.
You were on the right track.
What is going on is that there are too many columns to display for the size of your screen in the Events admin area.
The solution is to reduce the number of those columns (or get a larger screen).
You can do that by clicking on Screen options (located at the top right of the admin screen).
Simply untick unnecessary columns and the admin screen will look great again.

Let me know how that goes.
Best regards,
Geoff B.