Booting Up problems

After being on stand-by, the box doesn't start up. I've had to turn off at mains, some times more than once. But now it's not booting up at all.

My hard drive is usually quite full 97%+ - would that make a difference?

Thanks in advance.

Sent from my iPhone using Tapatalk
I'm not technical in any way. I don't know what a 2 hour circular buffer is? Can you talk me through it please?

Sent from my iPhone using Tapatalk
It's a '2 hour' file on the HDD so that you can pause/rewind 'live' TV. You couldn't rewind it if you hadn't first recorded it.
We normally start by assuming not customised unless otherwise stated. IIRC the topic was started here and then moved - but I could be wrong on that.