My home sharing stopped working last night after finishing a movie.

I had just finished watching a movie and had planned to watch a second one when my power began flickering. My apple TV then couldn't connect to the iTunes store so I restarted my apple TV and the only things that came us were computer and settings. I thought to myself that my cable/internet must be out. But that's OK because I've downloaded all my purchases from iTunes onto my computer and I'd simply stream the content from my computer. It didn't work. I was unable to watch any content through my apple TV. Yet, I could watch content on my iPod and my computer, but I didn't want to sit in my cramped study. Is there a setting I need to change so that apple TV can stream from my computer?