Thank you for that, tuna. 
I figured out what the problem was though. I’m using the 2010 demo, which I installed just today. I guess I should have mentioned that. 
But I had checked out one of the Face Robot examples and that automatically switched me to the Face Robot interface, which loaded back up even in a new scene after being closed back down.
I figured out how to close the Face Robot panel and get back my MCP and the left side panels, but trying to open the main shelf just opened it in a floating window.
Finally I figured out I needed to enable the Softimage Interface from the Face Robot tab at the top, to get it all back to normal.
Then each time I opened it back up it opened with the Face Robot interface until I figured out that I had to physically disable that.
Very confusing.
What can I say - I’m a n00b. 