Help please! Samsung LED 3D TV screen turns purple and no sound!

Hi there,

I hope someone can help! I have a Samsung LED 3D TV un55d6500 and it's only i think less than a year old. The screen has started, when i change the channel, to turn purple for a few seconds and has no sound. It will then change channels. Does anyone know what this is? And any advice? I am hoping it could be something simple...

Thanks,

Stephanie