how come my sidekick dies when i put my memory card in it?

[Jessica D]

okay so i have at&t and as yall all know sidekicks are t-mobile company so i unlocked it and i didnt have any troubles with it anywayzz i needed a memory card so i got a 8gb memory card i put pics and songs in it and now when i put it in my phone my phones dies i already tryed chraging it and unlocking it at the same time but it keeps on dying and my sim card isint the problem caze i took the memory card out and i just left the battery in it did not die when i turned it on! i need helpp plzzz!! whats goin on with my phone!! i would really aprreciate yalls help~