i had and i have the same problem
i think your IMEI is damaged
if you want to chek that you need to restor you iphone using
iPhone3,1_4.3.5_8L1_Custom_Pwnage.Tool_Restore_Act ivated.ipsw
you can find it here
http://hotfile.com/list/1834925/f6ab5eb
your phone will start but no imei no wifi etc