I'm having the same "Comments Off" issue as abrabennett, above, but I can't follow your instructions. You say "Go to the "screen options" tab at the top of the screen and activate "discussion" on the visual editor page".
I can click on "Screen Options", but there's no mention there of "discussion".
And where is the visual editor page? I can't find any page of this name.
When I click on "Screen Options all I see are eight titles with a tick box beside each (all ticked):
*Right Now *Recent Comments *Incoming Links *Your Stuff *What's Hot *QuickPress *Recent Drafts *Stats
Nothing about "discussion" or visual editor page.
In settings, "Allow people to post comments" is ticked.
But my most recent post still has "Comments Off" at the bottom.
Where am I going wrong?