Are you receiving any error message?
Sounds like the issue may be related to the SIM card. Please remove and reinsert the SIM card. If the issue persists, test the device without the SIM card. If that resolves the issue, please stop by a T-Mobile store to have your SIM card replaced.
If the issue persists, please contact HTC for further support. They will determine if the issue is related to the device, battery, or expansion card.
Hope this helps!
Thanks, I'll give that a try. From the other posts I've read on the board about similar situations, is there any way for you to see if my service settings are appropriate for Android? I'm concerned that may changed when I was doing my testing.
I'll let you know. Since I've already tried reseating the card several times, I'm going straight to running the phone without the card. The reboot cycle was only a few hours so I should have a good idea soon.