Getting 404 on all but one page of this site

I was moving some things around on the ftp and when I was done, certain pages were bringing up a 404…

The front page is coming up just fine but all others are getting a “404 Not found” message.

If I create a new page, I can view it in preview as a draft until I publish it, then it gives me a 404 again.

My programming knowledge is limited but I’m learning.

Any help would be appreciated!

Thanks