Windows has got the habit of saving almost anything you got your hands on, like recent run list, recent wallpaper, recent files etc.. Although some of these may be useful most of them are not. The recent RUN list, mentioned above, is saved in the Windows registry. (The recent Run list is useful but this is an example). If you take Start»RUN and type something you may perhaps note a drop down of the previous commands typed there.

These commands that were previously typed are saved in the Registry. Goto Registry Editor by typing regedit in RUN dialog. Navigate to the following folder HKEY_CURRENT_USERSoftwareMicrosoftWindows
CurrentVersionExplorerRunMRU

Here you will find some regWords with values of Run lists and name as a,b,c,d.. there will also be an MRU List which saves the order in which the Run list is to be shown. Delete all the keys except default . Now restart Windows Explorer (press ALT+CTRL+SHIFT and click CANCEL button on Shutdown dialog and start explorer again through Task Manager). Now take the RUN box and the recent commands will not appear any more.
Some related articles you may like :
- Find all recently used Wallpapers from your Registry
- How to prevent access to select drives using Registry
- How to clear full internet history from Internet Explorer
- Prevent copying of files to USB drive
- Add a context menu option to list all files in a folder and save it as text file
- First step to a cleaner and faster Windows – understand the Registry
- How to change the default wallpaper folder of Windows to your favourite one.
- View system files (super hidden) in Explorer