after effects error

Today I was going to continue the tutorial but my after effects document is having some serious problems.

Everything is black.

The video even renders black.

First I tried to research the problem but nothing helped, then I tried to delete the layers I had and start over but it stayed black. Now I am going to get a completely different video.

Initially the new video worked.

After a quick save I closed and opened it again and it was not black.

  Tomorrow I will hopefully be finishing the tutorial.