I hate when people use the run menu for some reason. Here are the steps for erasing the previous entries:
# Open HKEY_CURRENT_USER\ Software\ Microsoft\
Windows\ CurrentVersion\ Explorer\ RunMRU\.
# Delete all of the values in this key (everything in the right pane, except for (Default)).
# Close the Registry Editor when finished. You'll probably have to refresh the Desktop or restart Windows for this change to take effect.