Desktop is black and no icons.

When i turn on my computer the desktop is black and no icons show up. I can hit crl+alt+del and hit the start new task then press new task and i can access internet and other things. but i cant figure out how to get my desktop icons back up. I cant right click or anything tired to do what other people have done. my Norton virus protector says i dont have a virus. im so confused. some one help please.