How to clear windows run history

Windows stores the list of the commands we have executed from Run window. This ‘Run’ command history can be seen by clicking on the drop down list in Run window.

This history of  Run commands is saved in registry key which is specific to each user of the computer. One can clear this command history by deleting all values under this registry key.

This registry key is
HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\RunMRU

So to delete command history we can simply run the below command from command prompt.

reg delete HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\RunMRU /va /f

Note that after running the above command you would still be able to see history for the current login session. Once you logoff and login back you won’t be able to see the history.
The above tip is applicable to all Windows editions(XP, Vista, Server 2003, Server 2008 and Windows 7).

Source:
http://www.windows-commandline.com/2009/11/how-to-clear-windows-run-history.html