While some Dell computers can be restored to factory default by simply pressing Ctrl-F11 at boot-up, this feature isn't present in the Latitude series. The only way to restore a Latitude to its factory settings is through the use of a System Recovery CD. This CD is part of the purchase package, so you should have received one with your Latitude. If it is lost, you can order a new one from Dell.
Backup all the data you want to keep on an external hard drive, flash drive, or rewritable CD. Resetting your Dell to factory defaults will erase all data currently on your computer.
Insert the Recovery CD into your CD-ROM.
Reboot your computer.
Watch the text in DOS carefully. When prompted to boot from your CD, do so.
Choose System Restore and then follow the instructions presented. Once system recovery beings, it may take a few minutes. Once it's done, your system will reboot again.
Remove the Recovery CD from your CD-ROM and store it carefully. Your system has been reset to the factory default.