RAM, your computer's temporary storage area, loses all stored data when the power is turned off. Your pagefile is extra, RAM-like storage on your hard drive. It maintains its data even when your computer looses power.
The pagefile can contain unencrypted passwords as well as other sensitive data. While the novice user won't be able to see your pagefile while meandering through your computer, it's still a security risk whenever sensitive information exists on your drive. You can tell your computer to clear your pagefile of any information before it shuts down with a simple registry edit. (Always be sure to backup your registry before editing it.)
1. Go to Start --> Run and type "regedit" (without quotes.)
2. Go to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\Memory Management.
3. Modify or add the REG_DWORD entry "ClearPageFileAtShutdown" (without the quotes) and set its value equal to 1.
4. You must restart your computer for the changes to take effect.
This article was taken from TechTV