If there's no activity at all then it could be something as simple as a faulty rocker switch on the back.
Cheers. That would certainly make sense - it was the last thing I touched (to switch it off for a reboot) before it stopped working.
Do you think that could be fixed or replaced?
That's one of those Yes & No questions I'm Afraid.
Yes it is easy enough to change if you have the necessary skills but finding a suitable replacement might not be so easy.
If you're under contract then BT will replace the box free of charge.
The power supply units are known to fail, so its worth trying a suitable spare if you have one.