The following will clear the Run history manually:

1. Open the Taskbar and Start Menu Properties window. This can be done in the following 4 ways, & there may be a couple of more:

A. Press the Windows Key to open the start menu, press escape to close it & this will put you on the start button. While on the, Start Button press, Alt + Enter, to open Taskbar & Start Menu proberties. You will be on the Taskbar tab so, press, control + tab, to move to the Start Menu tab.

B. Press the Windows Key to open the start menu, press escape to close it & this will put you on the start button. Now, open the context menu with the application key or Shift + F10 keystroke, arrow up / down to, Properties, & press enter. You will be on the Taskbar tab so, press, control + tab, to move to the Start Menu tab.

C. You can also access the Taskbar & Start Menu properties by opening the Start Menu, select Control Panel, press enter, navigate to, Personalization Link, press enter, shift + tab to, Taskbar & Start Menu Link, & press enter. You will be on the Taskbar tab so, press, control + tab, to move to the Start Menu tab.

D. Press the Windows key to open the start menu, and then type Taskbar in the search box and hit enter. This will put you into the properties, so you will be on the Taskbar tab so, press, control + tab, to move to the Start Menu tab.

2. In the Start menu tab, tab a couple of times to the Privacy area & uncheck the, Store and display recently opened programs in the Start menu option. If you need to clear recently opened files from the Run Dialog, uncheck, Store and display recently opened items in the Start menu and the taskbar.

3. Tab to, Apply, press the spacebar, tab to, Okay, & press the, spacebar or enter to save & close.

so to clear the run dialog history, you uncheck the box which reads:

Store and display recently opened programs in the Start menu. Note: If you want to re-build your run dialog history, you will need to go back into the, Taskbar & Start Menu properties, and re-check the box, Store and display recently opened programs in the Start menu. Tab to, Apply, press the spacebar, tab to, Okay, & press the, spacebar or enter to save & close.