Writing is easy: All you do is sit staring at a blank sheet of paper until drops of blood form on your forehead. ~Gene Fowler
If this is your problem try Free Writing. This is simply writing whatever is on your mind whether or not it has anything to do with what you're writing. Just empty your mind and write whatever comes to it. Don't worry about your prose being incriminating. Remember, you can always hit the delete button!
Don't look at the screen while you type. This shuts down the evil editor completely! Turn the screen away and start typing your mind for about three minutes. Don't worry about mistakes just type. If after three minutes you want to continue, keep at it.
This is very cathartic and you will find in all your ramblings that you have some really great ideas. Do this over and over until that old buzzard gets bored and flies away in search of someone else's shoulder.
Give it a try and let me know how it worked for you!