On our second box, the first one not connecting properly. Just sent our second box back, this was working fine until we unplugged the main power switch to change the extension lead and now the box turns blue and starts to come on then the lights go off and it says there is 'no signal ' on the TV. I've tried unplugging everything, checked all the cables, factory reset etc and nothing will work. Getting very frustrated about paying for a service we can't use, and it's not filling me with confidence about BT. Any ideas what could be wrong?