Under chipset first.  Then install the Control Point drivers.

All here:

www.dell.com/.../advanced

Ahh ty.. But it terns out the dell updater program works on a diferint browser..

EDIT:

dame.. It did not fix the mising driver for Broadcom USH but it did find the PCI Serial Port and PCI Simpel Communications Controler

There is an order that must be followed when it comes to properly installing drivers.

www.dell.com/.../how-to-manually-reinstall-windows-7-on-a-dell-computer

Broadcom USH would be the ControlVault driver, and the others are probably the Intel AMT drivers.  Neither one would have anything to do with using an eGPU over mPCIe, though....

I dont see any thaing remotly to the discription "ControlVault" in the dell drivers area.

Really?  It's called ControlVault Driver right here, found by going to support.dell.com, selecting Latitude E6400 > Drivers, and then Windows 7 64-bit since that's the newest available: www.dell.com/.../driversdetails

And here are the two AMT drivers:

www.dell.com/.../driversdetails

www.dell.com/.../driversdetails

Ugh, for some reason when I try to add direct links, the posts get queued for moderator review, even though they're all links to Dell pages.  But go to support.dell.com, select Latitude E6400 (maybe DON'T specify your Service Tag in case that's incorrectly filtering out drivers that do pertain to your system), then select Drivers and Downloads, then the "Find it Myself" tab.  Change the OS to Windows 7 64-bit, then the ControlVault driver is under the Security section, and the two Intel AMT drivers are under the Chipset section.

Go to support.dell.com, select the Latitude E6400 (maybe DON'T specify your Service Tag in case that filters out files that actually do pertain to your system), select Drivers and Downloads > Find It Myself, then change the OS to Windows 7 64-bit.  The ControlVault Driver that will take care of the Broadcom USH device is under the Security section, direct link here.  The two Intel AMT drivers that will take care of those PCI devices are under the Chipset section, direct links here and here.