Inaccessibility of Mac OS X?

One of my relatives has just purchased a desktop Macintosh. Unfortunately she is totally computer illiterate. This is were I come in. I managed to get install one program and setup her internet access. (She came to me and said "I just wrote an email and it was not sent." I asked her if her email program was aware of her user namer, reply address, outgoing server, and incoming server. She replied that she had no idea what I was talking about, nor did she want to know.) I believe you get the idea.

Anyway, I myself have run into a problem which I hope someone can answer. I am disabled. As far as computers are concerned this has two ramifications: 1) I am unable to hold down two or more keys simultaneously and 2) I am unable to use a mouse. Now, I was able to setup both MouseKeys and StickyKeys on the desktop Macintosh but I am unable to discover how to use MouseKeys to 'drag' a window. I searched the Macintosh help system but came up empty. On the internet I read that I had to hold down the 'option' key as I moved the mouse but when I locked the 'Option' key and moved the mouse only the mouse moved! Is there anyone using Mac OS X who can tell me how to use MouseKeys in order to drag a window?

Thank you in advance for your reply.