I bought one SAMSUNg SGH-J700i. When I am trying to poweron the phone it asks for Phone lock password which is 1234 and opened but immediatly it asks for SIM loack password. But I am not awrae of any SIM lock pass word. Pl Help

If u enter PIN code incorrectly 3 times, PIN will be blocked n phone will ask you for PUK(Personal Unblocking Key). This is a 8 digit code. If u enter Incorrect PUK for 10 times Your SIM will be lock permanently.

Your cell phone service provider can(Call from other no. n ask tell them for puk of ur no.) give you the PUK code aft3r answering simple security question.
Later enter PUK than enter new PIN, confirm new pin. Go to -Setting
-Security
-SIM lock
-off
Disable SIM n Later Phone Lock
PS:(You have to block your PIN to get access to PUK,
Default PIN- 0000, 12345)