Originally Posted by carolocity
My phone kept rebooting, or looping, and taking battery out did not fix it.
I did fix it doing the following steps.
Pushed the down volume and the top off switch down at the same time. A black screen came up with little writing in the top left hand corner. I was able to scroll with the volume button to something called "recovery". I pushed the top on/off button. That made a green animation of the phone come up with a black background on for a minute or so, then a red triangle. I plugged the phone in and waited a long time. The red triangle went away, the 4 G white screen came on for a long time, and then my home screen started coming up, and I have all my contacts and pictures, did not lose anything!!!!!!
My phone had same issues yesterday and I did exactly as suggested by Carolocity up to the point when the red triangle appeared on the screen. I plugged the phone to charge the battery while waiting for the red triangle warning to disappear and proceed to booting. Till this morning around 11am nothing happened, the red triangle was still on. So I removed the battery, waited few seconds, put the battery back and pushed the "on" button and it booted just fine. All data from contacts, sms, voicemails, call history is intact! I'm now backing up the data to my computer and SD card. I thank God as it is a miracle. I had called Sprint and HTC support, all had one option, to reset the phone and lose all the data. I was not ready to lose my data. I thank God for this forum as I was miserable with the idea of losing my data.