Something similar has happened to me.
I installed TWRP and CM11 on it a few weeks ago. It had been running fine. A couple days ago I accidentally let the battery run completely out. Now it won't charge or power on.
It doesn't appear to be charging at all, doesn't get warm like it normally would when charging. Pressing the power button does nothing now, first time I tried to power it on I saw the plug image indicating no charge, but now I get nothing at all.
I've tried holding the power button for 30 seconds (and longer). I've tried holding the power and volume down buttons together. I've left it plugged in all night. It seems to be completely dead now.