To erase/delete traces of past activities including the last (15) opened documents/files in Windows XP, install freeware LCleaner (V.1.1.2.34 on 22-Dec-2007) from www.585Soft.com

For multiple users, manually remove each user’s list separately with individual log-in.

Right click on bottom toolbar, (or START), -> Settings -> Taskbar and Start Menu -> Start Menu

There should be 2 radio buttons, viz. Start menu and Classic Start menu

Start menu -> Customize -> Clear List

Classic Start menu -> Customize -> Clear

That’s it!