Dear Sir,
Your advertisement in Bangkok Post of May 19, 2015 for the position of Computer maintenance manager has attracted my attention because I think that my qualifications will fulfil your requirements.
I have a certificate to prove that you were trained to use computer skills. Consist of Computer maintenance, installation of programs. In addition, during my studies. I got an internship at a famous company in Supanburi. Which I can work out well. But since I'm having trouble getting it is necessary to move out, and I believe that computer skills were able to build my reputation were a great contribution to the Company's you.