so i just got this phone like 2 days ago. it was used because my brother gave it to me and it was used when he got it. anyway i dont remember what i was doing, but i went to reboot my phone, and i reboot it but when it came back on, it rebooted its self again. at first i thought OMG WHAT DID I DO TO IT and then i though well i hit the reboot button a few times and then i thought okay so it died. so i charged it up, and it came on and it was working for a minute, then it rebooted its self. it kept doing that and then it stopped and it was fine. but then yesterday i was downloading apps and the phone FROZE. like seriously froze. and i couldn't turn it off by the power button so i just took the battery out and put it back in, tried to turn it back on, and now its stuck on the tmobile G1 screen!! everytime i try to turn it on it keeps getting stuck there. ive tried taking the battery out for a few minutes and putting it back in but its not working. WHATS THE PROBLEM?!