How do I restore Fastdial as my homepage? Any help would be appreciated...

OK....

Go to the Firefox/Tools/Options/General Page

If what you say happened you should see the comcast address in the home page field.

The simplest is to select:

when firefox starts show a blank page

but if you click on home page you might still get comcast.
so:

option 2
set:

when firefox opens show my home page
(probably set already)

and in the homepage field enter
about:blank

(in that way you will probably remove the comcast setting which was probably in the home page field, so good to do)

that should do it
Let us know how you get on...