Excel 2010 DEFAULT date format - How to set it

I've read the posts and no suggestion (note that I said "suggestion", not "solution") worked. Why is the date format set to d-mmm anyway? Who uses that?

How do we set default settings for ALL worksheets and workbooks? Is there a template that we can modify?

Setting to use 1904 format DOES NOT work.

Setting the -click on Spreadsheet TAB... View Code... Enter this... Does NOT work for future workbooks. It is for ONLY THAT SHEET and not the entire workbook anyway.

And, please do NOT reply with how to set it for the current worksheet - I know how to do that.

Thank you.