so i just bought my phone from craigslist today. it's a 3g 8gb and it had OS 4.0.1 on it. it was really laggy so i downloaded 3.1.3 and tried to downgrade it. all of a sudden it asks me to activate my phone. im using t-mobile btw. about 3 minutes later, the screen turned all white and there's nothing i can do about it. i had to hard reset it and when i turn it back on, it's still white. i still see the apple logo as it boot up though. what happen? how can i fix this? this phone was $230 =[