Not sure why the board would shut down on you? Can you clarify what you mean?
Websites and forums are "broadcast" to the internet, similar to how TV is. The only restriction is that you have to be logged into the forum to post. When you log onto the forum, there is a cookie placed on your computer. If you select "remember me" when you log in, the cookie becomes permanent. Do you have a cookie "eating" program running that is deleting that cookie?
As for the fonts, "Edit Your Profile", located on the right sidebar, allows you to adjust the default font size from small, normal, large and largest.