closed registration / admin approval message

Hi, im wondering if there is a way for me to place a message on the front page of my site when i close registration. What i would like to do is have a message being displayed stating the reasons why the registration is closed. Also when some one signs up is there a way i can edit the T&C's of signing up? i would like to mention in there that the site is to be kept private and not to be advertised anywhere. This is due to the fact that im tired of having to clean up the boards due to spammers. So if its written in the T&C's on sign up then no one has an excuse when i ban them from my board.

Try the annoucements, or the homepage message.

You can restrict all guests from seeing your forum via the forum permissions.

you can do that by typing your message to admin panel>display>generalities>(homepage message)message content(add there)>save

as stated by dotdavid, you can also use permissions for guests to not see the whole forum unless they register on it.