Writers block!

I have been asked to write a letter to a potential employer. Expressing to them why I want the job. The unfortunate thing about this job is, I really want it. If I had to write out what I wanted in a job, this covers 90% of my requirements. So why am I finding it so difficult to sit down and write the letter? To avoid it so far I have had a lovely long shower, eaten some chocolate. I am currently eating pickles on toast-- to the horror of my family. I tried to explain to them it is comfort food. It is something from my childhood. It is now time to make a cup of tea. *sigh* I am running out of excuses and time. It isn't something I want to rush...I will be back after I have put pen to paper.