Disable comments completely

I would like to be able to disable comments completely from my blog for the time being. I would like to enable them at a later date.

How do I do that so that even the “Comments” option at the bottom of each post disappears? I don’t want viewers to think they can post comments at this time.

If I have to go into the Comments html page, can someone tell me exactly how I have to alter it?

Thanks.