Plist file question

Dear members, Will deleting the mail plist file give me a fresh new start? since I don't have a mobile me account and I only what a basic mail account. Mail keeps trying for find mobile me and ask for a password! I have a gmail acc and strangely my name now appears above that with a searching indicator to the right next to it. When I first purchased my last june I made the mistake of trying to set up a .mac acc that never worked!