My recommendation would be to goto a Samsung service centre and tell them your exact problem. Usually there is a software which can communicate with the filesystem of Samsung mobile (however its not available to general users). The official software SamsungPcStudio would require coupling of the mobile via Bluetooth or cable, which in your case would not be possible due to password lock at bootup time.Hopefully they would not be charging you if your phone is still in warranty period. Anyways just make a visit to service centre and be at peace