Here is some advice that may help since I have been doing it on my Nokia phone. Just remove the battery and leave it off for some hours and return it. Looks simple but may work. If it doesn't wok you may want to take it to a Nokia shop for customer care.

the T-Mobile logo pops up then a blinking battery with a red bar in it and a outlet sign starts blinking in front of the battery. Then in a few seconds another empty battery appears with a blinking question mark appears and after a few seconds it restarts. repeatedly. I bought another battery thinking it was something to do with the battery but the same thing happened. PLEASE HELP!!