Hey Chet,
Sorry to hear about your writers block. Happens to me all the time! I am not sure how you are trying to attack the essays questions (particularly the WHY MBA question), but I would recommend taking a step back and think about 2 things...
1 - What makes you different from other candidates. What are your interests, passions, experiences
2 - What is your story - looking back on your pre-MBA and post-MBA life, what are the common themes. How can you craft a story based on what you have done and what you want to be doing.
Once you craft a unique story, then start building upon areas that will get AdComs attention - sell your pre-MBA experience, explore your post-MBA interests, explain how the MBA will help you bridge your pre/post MBA lives.
Very high level suggestion here, but hopefully can help you take a step back and re-engage.
Good luck!
NP
Nikhil P. | Admissions Consultant | Veritas Prep