LG u900 urgent help
 

have LG U900 mobile. it is
fully dead and only blinking 3
when am attempting to switch on.
i don't know well about flashing. i
have a cable for U900 and also i
have updated z3x latest shell.
when i'm trying to run and
downloading the support files it
says no card or no card found. i
don't have box. please help me
urgent. is that box must have or
not. ? please help me. if the box is
unnecessary why do it shows no
card?. and what can i do.? explain
me please. and immediate. and
also give me the links to download