Earlier we saw how to disable the confirmation window when emptying the Recycle Bin in Windows XP and Windows Vista. Here is a Registry hack to accomplish the same in Windows 7, using the excellent NirCmd tool. This registry hack replaces the Empty Recycle Bin command with NirCmd command-line so that the Recycle Bin can be emptied silently without any prompts. This also works from the Recycle Bin Tasks pane.
Using NirCmd to Silently Empty the Recycle Bin
1. Download NirCmd from Nir Sofer’s site.
2. Unzip and move NirCmd.exe to the C:\Windows\System32 folder.
3. Download w7-empty-bin-silent.zip and save to Desktop.
4. Extract the files to a folder, and run the file w7-empty-bin-silent.reg.
This replaces the Empty Recycle Bin command with "NirCmd.exe emptybin" command-line. Now, emptying the Recycle Bin either from the right-click menu or from the Tasks pane in the Recycle Bin, should not produce any prompts. There is also an undo REG file available inside the above zip archive.