Excel won't let me modify a cell Style

[MartinGM]

I created a new Style, but mistakenly I included the "Locked" property.

OK, I thought, I'll modify it.

But Excel wont let me do that because it says that the Worksheet in locked.

I've been right through the Workbook and unprotected all of the Worksheets, but I still cannot modify the Style.

Oh well, I'll delete it then and start over.

But Excel won't let me do that either, for the same reason.

How can I back out of this trap ?