I have an HTC Desire 626s. Next month will be a year since I got it, I bought it brand new from Verizon. The battery wouldn't charge so I bought a new one and replaced it. The phone came on just fine. When I plugged it into a charger the phone got hot and now it won't do anything. I've even tried hard reset with the hardware keys but still nothing.
A year old phone's battery really shouldn't need to be replaced unless it has extremely heavy usage. Therefore, I suspect something else is to blame.
The most likely suspect is the USB cable you're using to charge it. It may be damaged or completely non-functional.
The second suspect could be the AC adapter, better known as "the brick" that you plug into the wall with a USB port on it. It may no longer be putting out any power, and your phone wouldn't charge even if the phone is plugged in.
Lastly, and unfortunelty most drastic, is that something has happened to the charging hardware within the phone. There is a system within nearly every rechargable electronic device that regulates the process of charging the battery. If it is damaged, your phone will never be able to charge again.
To diagnose the actual issue, try a different AC adapter and/or a different USB cable. If your phone begins to charge, then those are broken. If using both a different AC adapter and USB cable and the phone still won't charge, it's likely that the phone has taken internal damage to the charging mechanism. This isn't a cheap fix, and you'd be better off just replacing the entire phone.