Letters / A formal letter I want to write to a notebook provider [2]

<I just want to convert my thoughts into formal sentences. Please help me. I'd be very thankful if you could rewrite my entire letter. Thank you so much indeed>

Dear Sir

I purchased successfully a notebook from your own shop three days ago. The machine had worked very well until yesterday evening. I brought it inside my backpack and cycled about 20 minutes home. After getting back home I putted it on the table then powered it on but it won't boot any more, just black screen and no leds were lighted. I have checked the power supply and it worked fine. Everything outside the notebook don't look unusual or damaged at all.

Please tell me what should I do. Could I be able to return it back and get another the same one?

I would be very grateful for any helps you are able to provide.

Best regards