Dell Latitude E6400 XFR (Mid 2008) - Manual (Page 29)

Dell Business Client E-Family Re-Image How-To Guide 29
Touch Screen Digitizer (E6400 ATG only)
Microsoft XP 32-bit and 64-bit, and Vista 32-bit and 64-bit operating systems
do not include the Digitech digitizer driver and application. Install the
following drive and app provided by Dell, found under Input Device Drivers
on Dell's driver and downloads support web site (support.dell.com):
• Digitech Touchscreen driver - E6400ATG