If you are very much concerned about your sensitive data sotred in your system and worried about if any one can read/access it once you have shutdown your system, then erasing the swap file at the system shut down will be the right choice for you to. Swap files is the collection of data you used in binary form which generally can be accessed through a remote area. There is only a small tweak into the registry which will force your system to rewrite the swap file from zero whenever you shutdown your system thus leaving no valuable data stored in it. Settings are described in the next para but make sure to implement these settings if you are only very serious about your data theft as it can cause to take longer time in shutting down the system and for a common cause it is not a advisable idea.

So to implement these settings go to registry editor using regedit in run command and look for the following keyword

HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\Session Manager\Memory Management

Set the ClearPageFileAtShutdown DWORD to 1

The new settings will be implemented however if for any reason you want to revert back with your old setting then set it to Zero.