You’ll have to logoff and then back on, but the list should be clean.
Right-choose the taskbar and choose Properties, then choose Start Menu.
go for the “Classic Start menu” option, and choose the Customize button.
Clear Recent Commands From the Run Dialog in Windows XP
Has it ever bothered you that there isn't an obvious way to remove the previous items in the Run box in Windows? It's often very useful, of course... but if you are just a little bit paranoid you might want to clean out that list on occasion.
