Think my phone is dead. Won't boot. any ideas?

I've been having a few issues with my Nexus 4 on 5.1.1.
Twice in the past month I've had random Force closures of all aps. Facebook was the worst. But then it goes on to all other apps including the launcher.

First time that happened I did a factory reset and things went well. Yesterday it happened again while it was on another charger and I can get my phone to boot.

The screen backlight looks like is on when it's plugged into the charger and will go out if I hold the power button down for 5 to 10 seconds.
If I hold the power button down for 10 seconds when the charger is connected the LED flashes red till I take my finger of the Power button.

I've let it charge overnight (12 hours) and I've tried holding both volume buttons with the power button.
As well as Volume up and Volume down separately with the power button.

Is the phone dead? anyone got any ideas on how to bring it back to life

I've got a screwdriver set on order as I don't have fine enough star screwdriver to remove the internal battery connection. Which is my next step..