Here are the detailed instruction on resetting your device. If this does not fix your issue, you may need to take your phone to a service and repair store.
1.Start with the phone on. Note: The phone can either be locked or unlocked.
2.Just press and hold the Power button.
3.Keep holding down the Power button until the screen turns off.
Note: A warning message will popup telling you that the phone will reboot at the end of a 3 second count down. Ignore this message and keep holding the power button.
4.Press and hold the Volume Down button.
Note: The phone will reboot normally if you do nothing at this point.
5.Release the Volume Down key when a white screen with three skateboarding Android logos appear on the bottom. The following options will also be displayed:
6.Press the Volume Down key to scroll to FACTORY RESET.
7.Press the Power key to select the highlighted option.
8.The phone will reset and reboot.
Note: There is no confirmation screen. Once factory reset is selected there is no way to go back. This reset will also erase the built-in storage but not the removable memory card.
As mentioned above, Long press the Power Button until the phone restarts. IF it starts normally and runs fine, disable Fast Boot,
Touch it to disable, i.e. no Green check.
If it still reboots, try booting to Safe Mode, Long press the Power Button until it reboots and at the first white boot screen, press and hold the Volume Down button until fully booted. You should see Safe Mode in the bottom left corner. At that point, disable Fast Boot as described above. Reboot phone to exit Safe Mode.
The difference between a Fast boot and a normal boot are minimal on these phones, so I just leave mine disabled.
I tried rebooting several times but it just wouldn't get past the HTC screen. In the end, I took it to a Sprint repair location & they had to wipe everything off the phone. My contacts & pics were saved on Google & Dropbox but I lost all the apps I downloaded. I never backed up the phone :-( Anyway, it's back to working condition! Thanks for the feedback everyone!
You can retrieve a list of the apps installed, not the data but the apps themselves by going to the My Apps section of Play Store,
To get to the All Tab, swype the screen from Right to Left. You will see every app you purchased or installed listed there after your phone has synced with Google.