To Clear Recent documents history, Run, Open/Save box MRU and Typed URLs
To clear the recent documents history, the entries under Start-RUN dialog, Open/Save as (Common Dialog) boxes dropdown file lists and the typed URLs in the Internet Explorer Address bar, try this:
For XP Start Menu:
Right-click Taskbar, choose Properties, choose Start Menu tab
Click Customize, Advanced tab, and click Clear List button at the bottom
For Classic Start Menu:
Right-click Taskbar, choose Properties, choose Start Menu tab
Click Customize, and click the Clear button
Click OK, OK and close the dialog.