Follow these easy steps to disable delete confirmation dialog box in Windows 7:
Right-click on the Recycle Bin icon on the desktop.
Select Properties from the resulting menu.
The Recycle Bin Properties dialog box will appear.
Uncheck the Display delete confirmation dialog box at the bottom.
Click on the Apply and then the Ok button.
You have been successful to disable delete confirmation dialog box in Windows 7.
The method to turn it on again is very simple too. Just follow the
above steps and check the Display delete confirmation dialog box.