I'm researching this. Does the country you're from have V-chip technology to block broadcasted content? To be honest, I've read on this briefly this evening, and I'm unable to determine if that technology exists in all regions. If there is no technology such as the V-Chip technology in your region, you may be limited to blocking specific channels.

What do you mean by "block the TV completely"? To not let anybody watch any channel? I don't believe that can be done. If you meant something different, let's explore that.