Could someone correct my grammar please? (16FEB)

I would be grateful if some can help me correct my mistake.

And also this one :

Thank you so much!

Q:
You would like to buy some electrical goods at a shop in a nearby town.

Write a letter to the shop and ask if they have the things you want or whether they will be able to order them. Ask what the prices are and how long they will be able to hold the goods for you.
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A:
Dear Sir,

Your recent advertisement on newspaper said that you are the biggest electrical good shop in London. I am writing to enquire that if your company can help me find a computer mainboard that the mode number is "Intel Px8 V.50".

I tried to find this mainboard for many different shops before, however they said that this was already out dated and only able to be found in second hand market. I wonder if I will be able to order from you since you are the biggest electrical good ship nearby.

Please let me know the prices of the goods and how long you will be able to hold the goods for me if possible.

I am waiting for your earliest reply

Regards
Assman