Hi, Alihyde75,
Thank you for visiting Sony Community!
PCG-51211M is not being recognized by our system. It is probably the chassis number or a non-U.S. model. If your computer has an Assist button, you may use that instead. Simply press the Assist button while the computer is off. It will give you the option to reset the unit to factory settings.
For further assistance, we kindly recommend visiting our Sony Global Website for information on contacting the Sony Support Center in your region at http://www.sony.net/SonyInfo/Support/. Due to proximity, they are in a better position to respond to your questions or concerns.
Regards,
Vincent
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