Scrivener suddenly won't compile

Hi,
My project won’t compile and I can’t get any details on the project statistics either. It has compiled fine until recently but I am not very ICT literate so I may well have pressed the wrong button or done something wrong.
The Trash folder, which is usually at the bottom, has somehow moved to the top, so I don’t know if this is linked.
The document consists of about fifty short files in the binder. When I was attempting to fix the problem, I have somehow managed to enter them as a “new collection.”
When I click compile it says: "no file was generated as the compiled document was empty. Check that you have selected at least one document from the contents pane that contains text, also select you have valid items selected in the “Formatting pane.”
Please can somebody help me? This project contains my heart, soul and hours of blood, sweat and tears!

Looks like you’re Compiling an empty Collection. Change the Compile: drop-down list above the rightmost column in the Compile Overview window.

Thank you. I don’t know how to do that though! When I press Compile, I don’t get a drop down menu. It just asks how I want to format it.
It seems to think it’s an empty document but the binder has loads of files in it.

What version are you on? 1.9 or 3.0?

In version 3, the screen that appears after you click Compile is called the Compile Overview. This window has 3 columns. The Compile: drop-down list is above the right-most column.

GemCompileCollection