[Lremy22]

I had the same issue and I havent flashed any ROMS it seems to be a device issue which sprint and HTC will deny. However what I can say is that when I did a hard reset it took care of the problem with the phone not answering calls sometimes it can be a conflict between a third party app and the phone itself but a hard reset should fix your problem. Just make sure to back up your stuff and pay close attention when you install things to your phone so you can spot the problem file

Hope this helps