All Cells Defaulted as Date

I'm using Excel 2007, and when I open a new workbook all of the cells are defaulted as the date format.

How can I change this so it is in the general format instead?

For example, if I type the number 1 in any cell, instead of returning 1, it will return the date of 1/1/1900.

Thanks!

i saw a possible fix for this the other day ,click any cell and have a look have a look in your custom formats and see if there are any that start
[$-409]
like
[$-409]dddd-mmm-yyyy..." and delete them thats using the delete button in custom formats not just clearing the window.