Clear Recent Commands From the Run Dialog in Windows.

The Easier Way is,

• Right-click on the taskbar and choose Properties, then choose Start Menu.
  
  
• Select the "Classic Start menu" option, and choose the Customize button.
  
  
• Now just click the Clear button to remove all of the recent documents and applications from the start menu.
  
  
• Once you've done that, hit Cancel and then Cancel again to make sure you don't switch to the Classic Start menu.
  
  
• Note that this method will clear out everything… so if you just want to remove a single entry you need to use the registry hack method.