Thanks for posting and welcome to the forum!
If it is the graphic lock/pin-code you have locked you need to perform a repair of your phones software to lock it up.
You perform the repair with our program Sony PC Companion, available for download from the link below.
Start up PC Companion and the section in the program called Support Zone without having the phone connected with the USB-cable. Then select that you'd like to update and then click on the blue text that says "repair phone". After that you'll be guided through, step by step.
http://www.sonymobile.com/se/tools/pc-companion/
please help me!
