i had this problem...i stumbled across a solution that worked on my computer..you could give it a go:-
1. open any windows explorer window
2. rightclick on the toolbar
3. make sure that 'Lock the Toolbar' is unchecked
4. goto to windowsblinds, select the toolbar you want and apply changes
5. go back to the explorer windows and rightclick the toolbar and select 'Customize'
6. in the customize option, click 'Reset' and change the Icon options to Large Icons (if set to small icons) or Small Icons (if set to large icons)
7. Click 'Close' - and BINGO ! - your icons have changed - you can now go back to the Toolbar options and reset your icons to whatever size and configuration you want, and lock the toolbar again
if that doesn't work, just try playing with various options in 6. and hit 'Close'
i hope it helps