Troubleshooting “program does not contain a static 'Main' method” when it clearly does…?

Question

My MS Visual C# program was compiling and running just fine. I close MS Visual C# to go off and do other things in life.

I reopen it and (before doing anything else)

Answer 1

That's odd. Does your program compile and run successfully and only fail on 'Publish' or does it fail on every compile now?

Also, have you perhaps changed the file's properties' Build Action to something other than Compile?