Hey everyone, So heres the deal. The other day I decided to replace my battery/back housing/back casing. i had the part shipped in and i went to work at replacing it. I followed several step by step guides and it went smoothly. but now theres a problem. my iphone 3GS after being put back together turns on but doesnt recognize my SIM card. ive checked and my SIM card works fine in other iphones just not mine. So, long story short i need to find out whats wrong with my iphone and why it wont recognize my sim card. HELP me Please!! Thanks in advance!