Device not powering up

Hi All,

I'm a bit of a noob, so apologies if this is in the wrong place.

I've been happily running my device for a little under a year now with next to no problems.
I went to use it at the weekend and the device wasn't on (having put it on standby the previous night).
It now will not power up at all; pressing the button just does nothing (no light etc.).
I've checked the power adapter with a voltmeter and there's power coming out of it, and when plugged into the device there's power to the...

Device not powering up