404 error code

all of my pages except the first one have the 404 error code, page not found. It was good this morning, but now it is doing this. My site is http://www.onlinepsychicadvisors.com. The first page, Psychics, is good, the register now, and the chat page are good, I don’t understand what happened to the rest. They are all published, I tried doing a restore with yesterdays date, but nothing is working, please help!! and I don’t understand how to put tags on the psychics page. I tried doing a link, which was working to show an additional page to their picture when it is clicked on, but now, that isn’t even working! What can I do to resolve this?