Apple Tv HDMI problem?

I just got apple tv the other day and hooked it up to my toshiba HDtv using an HDMI cable that I also just bought. After setting up the apple tv and getting everything situated I sat down to watch a movie, less than 5 minutes into the movie the apple tv lost connection and played the "No Signal Found" message. I unplugged everything and restarted the system. This keeps happening now, every time I try and watch something the screen with get fuzzy or flash and then cut out to the NO Signal. Is this an HDMI cable problem or should I take my apple Tv back to the store?