Brushes directories are messed up. Can I put them back to the default?

[Blighty]

There are 2 places where brushes are kept.

The default gimp brushes are here:
C:\Program Files\Gimp 2\share\gimp\2.0\brushes

The brushes that you add yourself are here:
C:\Users\your name\.gimp-2.8\brushes

There are pointers to the above in
Edit > Preferences > Folders > Brushes

Which brushes are messed up?
Have you made any changes to any of the above?