hello. My name is***** can help you with your question.
The first thing I would suggest doing is removing the battery which will completely shut off the phone. Then reinsert the battery after a minute and let the phone startup. At that point you should be able to get to the boot up. If you cannot, it may be something a little more serious than a restart. If this fails to help, exactly what part of the startup do you get to?
was impossible that you locked it without a password? There is a feature in a recent version of the operating system allows you to hit the upper left physical button to lock without a password. Then you would just unlocking the same way.