My HTC M8 has been failing and is becoming unusable. The phone will not open or will force close all apps, repeatedly freezes and reboots while performing simple tasks, and lags on all levels. I have cleared the cache and unused apps/data, I have moved nearly every file and program to the SD card, I have done a soft reset and a factory reset. After the factory reset I have installed very basic apps in hopes that would help yet it does not. The phone continues to get worse and is becoming unusable. What is my course of action aside from going to the store and running through the same processes that I have already been doing myself?