Always best to start a new thread of your own. That way we know what OS you are using and can deal with your specific variant of the problem.
Assuming you've backed up your Inbox emails, what do you mean when you say "I can't even delete the inbox file"?
When you go to Windows Explorer (or My Computer) and Find the file Inbox.dbx you presumably try to delete it. What exactly happens then - is there some sort of error message or does it just ignore you?