See if the below helps you any, the resource URL is at the bottom.
Turn on the computer and tap the "F8" key several times to load the
"Vista Advanced Boot Options" menu.
Click or use your keyboard's directional keys to select "Repair Your
Computer." Press "ENTER" to open the "System Recovery Options" window.
Select the appropriate keyboard layout for your Dell Latitude E6400
laptop computer. Click "Next."
Click "Dell Factory Tools," then "Dell Factory Image Restore." Click
"Next."
Click "Confirm Data Deletion" to proceed with the system recovery
process. After clicking "Confirm Data Deletion," you will no longer be
able to backup data (images, movies, document, etc.) files from the
computer and the partition will be formatted. Ensure that you have
backed up your system data onto another computer or removable media
device before proceeding. The recovery process will take approximately
five minutes.
Click "Finish" to restart the computer. Allow the operating system to
boot up completely, which completes the recovery process for your Dell
Latitude E6400 laptop computer.
RESOURCE: http://www.ehow.com/how_8005941_recover-latitude-e6400.html