HTC One XL dead topic

Hello, I have this HTC One XL that appears to be dead (it died while charging at about 90%) according to the owner and he wants me to fix it.

I have encountered this issue on the HTC One S before and a simple battery pull seemed to fix it, so I opened this phone up, pulled the battery, left it there for awhile, put it back on charge - no led, no response to power button (or any other combination of buttons) like before, plugging it into my computer also did not give me any driver prompts. I measured the battery with my multimeter - it says the battery is at about 4+ volts.

any ideas?

Thanks :D