Complaint letter advanced level

Hola dentro de poco tendré la prueba de certificación de nivel de avanzado en inglés. Estoy practicando y acabo de terminar una carta. Le agradecería me la corrigiera y mi diera su punto de vista. Le agradezco de antemano su labor. Gracias.

Federico
Martínez Alfaro
Marques
de Molins, Nº2,
SPAIN,
ALICANTE, 03004
4th June 2013,
CUSTOMER SERVICE DEPARTMENT
LONDON, UNITED KINGDOM
E1 GPH
To whom it may concern
First of all, I would like to let you know that,
the main reason why I decided to buy a last generation computer throw one of
your branches was due to the good comments other customers had written in your
website.
Lamentably, problems started, as soon as, I
unpacked the cartón which contained it. On one hand, the drivers which are
necessary to install all the programs that are required to run correctly the
computer such as; the operating system, the graphic card, the keyboard, etc. We’re not there.
Furthermore, every time I was trying to turn
off the computer a blue screen appeared showing that there was an error and it
was impossible to me to deal with it. On the other hand, after I had done all
the connections with their corresponding wires a very loud sound was hearing,
like if there was a problem with some component.
Due to above mentioned, I have been trying to
get in touch with the manager of the branch which sold me this item, but to
date, it has been impossible. Because all mentioned, I have been seriously
considering the possibility to get in touch with a lawyer, although I believe
we could find a better way to deal with this situation which is causing me a
lot of troubles.
For that reason, I will look forward to your
reply and the resolution of my problem.
Thank you for your attention in this matter.
Yours faithfully,
Federico Martínez