Monitor not working in docking station

I have a Dell Latitude C400.  It has XP on it.  We have already re-installed the OS hoping that would take care of below problem with no luck.

 

As soon as you undock the laptop and boot up as a standalone, the display reverts to using the laptop display only. When you go to dock it again, it holds on to that setting and only displays on the laptop. To get it back, I have to attach the monitor to the laptop itself and toggle (F8) until I can get them both showing. Once I do, I power down and put it back in the docking station. Again, it retains the setting and bingo, it works. But as soon as you undock and boot up alone, it switches settings. Was on the phone with Dell Support for a couple of hours and they say they don’t know why it happens.  All Drivers Bios,Video...etc are the latest.

Please Help.

Thanks