I think I might have ‘blog fright’

At multiple times during the day I have thoughts come to my head and I think ‘I should really put that down on paper or on my blog’ BUT when I get in front of my computer to write it down the thought completely disappears.  What is the deal that I cannot get thoughts from my head to my hands to write/type out?  Its kinda frustrating as there are a LOT of thoughts rolling around in this head of mine!