You tube isn't working, black videos?

I have two computers, on both the apple computor and the windows computor that are both using the same internet at my house, I can't watch you tube videos, the screens where the videos should be are black. This is just since yesterday afternoon I was watching you tube videos then and at 8 o clock at night I tried to and it didn't work. I don't know if it's related but I also try to click on the (Show the comment) link below a coment and it didn't work.