I had the same thing happen last night. I thought it was maybe a buffer thing but the box froze on channel 5! Me with no patience turned off the box and unplugged it. As of now, it's working again. Don't ask me how.
Btw, I disconnected the dish's coax cable yesterday morning and it ran fine up to when it was silent. I don't suggest unplugging it, but it worked for me. Just let it sit there and hopefully it will be ok. All the memory settings were intact when I replugged mine. Good luck.