The Run dialog box in the Start menu stores a list of more recently used (MRU) commands typed earlier. This article describes how to clear the RUN MRU entries.
Store and display a list of recently opened programs
The Run MRU entries, Common Dialog file name MRU, and the Typed URLs listing in Internet Explorer are now cleared.
Note: Disabling the above option deletes the Run command entries and prevents storage of recent entries for the Run command.