I wouldn't use the above 'fix'...
In W7 there shouldn't be TOOLBARS, and TASKBARWINXP is there, but it holds a lot of info of what is on the bars, ALL of them. Delete that and you'll need to start over.
It doesn't solve your problem either, it is really to fix the TaskBar not auto-hiding.
Also some INCOMPLETE instructions. Titi seems not to have pasted in everything. Might have gotten it from HERE.
Open Task Manager and Regedit.
<shift>+<ctrl>+<right-click> on the Start Menu & select 'Exit Explorer'
In Regedit, navigate to:
delete the value named 'Toolbars'.
In Task Manager, select 'File' -> 'New Task' -> type 'explorer' to restart
If that doesn't do the trick, repeat deleting 'TaskbarWinXP' as well. (I
can't test right now).
Exiting Explorer will collapse the desktop and save the data it has to the Registry. You can now edit and restart explorer.
If you ARE going to do this, I strongly urge you to EXPORT that key before you do anything so you can restore it if necessary.