When you shut down your NT machine, the pagefile retains anything that was stored during its last access. This can be a security problem if someone gains access to the page file.

To make the inactive pages in the page file fill with zeros, make the following change to your registry:

[HKEY_LOCAL_MACHINESystemCurrentControlSetControl Session ManagerMemory Management]
"ClearPageFileAtShutdown"=dword:00000001

Note: Please remember that editing your registry is potentially risky; always have a verified backup before you begin.