Before contacting the after-sales service, perform the following simple checks. They may save you the time and expense of an unnecessary service call.

 

When you switch your phone on, the following messages appear

Insert SIM Card
 Check that the SIM card is correctly installed.

Phone Locked
 The automatic locking function has been enabled. You must enter the
    phone's password before you can use the phone.

Enter PIN
 You are using your phone for the first time. You must enter the Personal
    Identification Number supplied with the SIM card.
 The option requiring that the PIN be entered each time the phone is switched
    on was enabled. You must enter your PIN and then disable this option if so
    required.

Enter PUK
 The PIN code was entered wrongly three times in succession and the SIM
    card is now blocked. Enter the PUK supplied by your network operator.