A tiny addendum to Milo's input. In my non-techie experience, when one pulls a power lead and battery, it is worth leaving them pulled for a while, say, enough time to make a strong cup of tea, at least.
I have no idea why this needs to be so, but I now do this with all my techie problems, (Sky, BT modemrouter as well as pcs), as sometimes taking the lead out and putting it back in a few seconds later doesn't work.