Firefox doesn't do email, it's a web browser.

If you are using Firefox to access your mail, you are using "web-mail". You need to seek support from your service provider or a forum for that service.

If your problem is with Mozilla Thunderbird, see this forum for support. http://www.mozillamessaging.com/en-US/support/
or this one
http://forums.mozillazine.org/viewforum.php?f=39

you are correct, I am using an email program...Yahoo! I had created folders that line up on the left side of the page, next to the email inbox that is open with all the emails showing....I wanted to delete the folders and start over with new folders, without emptying them, or renaming them......

I kept trying, and found out that selecting the folder, and actually hitting the delete button on my keyboard.....and it worked!!! what do you know!...I thought there must have been a super secret keyboard trick...and I feel ashamed I didn't think of that(selecting and typing the delete key) before posting the question...I want desperately to reorganize my email, with customer names, before starting over with new folders.

thanks for your quick response...anyway.