How to Clear Page File at Shutdown in Windows Vista

Start
Run
Regedit
OK
Navigate to:
HKLM\SYSTEM\CurrentControlSet\Control\SessionManager\MemoryManagement
set the 'ClearPageFileAtShutdown' value to 1
reboot system
Windows Vista will clear the page file every time the system shuts down. This will slightly lengthen the shut down process but will increase the security of the system.