Cannot turn Comments off

(1) I cannot suppress comments, even for a single post.

(2) I have never been able to get an email notifying me there is a comment waiting …

regardless of what boxes I check/uncheck for a single post, “Page Options, Display Discussion, Comments, or for “Discussion, Allow people to post comments on new articles”), and I have a valid email address in the Settings.

I have Theme Twenty Ten 1.2.

Any help will be appreciated. I have read most of the previous posts on this issue and nothing has worked.