Dang, what a weird design. The lens needs to go threw a cycle before it can reach the idle position where it waits for a comand from the user. If its in the closed position and you turn it on it extends to its full range then stops at the idle position. It sounds like it is stuck in some spot between close and idle. Since it cant reach the closed position or idle its shutting down. The only way to get it to work is to try and free the lens so it can cycle threw. There must be a lip on the slider and the lens is stuck on this lip so you cant slide it. Remove the batteries then try and slide the door open try and slide somthing between the lens and the door to free it up. This is the only way to get it threw the cycle. It may need to be serviced It sounds like the switch for the slider door is warn or has broken. It may work again if you can free the lens.
Ok not turning on is kind of vauge. This is what I would recomend trying. First off pull the battery and put it back in it should automatically boot in about 5 seconds. If this does not work use the power button slider on the side of the phone. If that does not work use your stylus in the reset button found on the bottom of the phone on the left hand side this should restart the phone after you remove the stylus. If that dosent work you can do the master reset and try that. If that dosent work I would say that you are out of luck with your phone.
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