Any way to lock down a screen resolution in Windows XP pro Sp2?

CEO has a new Dell XPS M1330. The laptop is working out very well. The only issue is that there is not option for a Dell port replicator so we have had to use 3rd party. We found the kensington to work well, it does LAN, VGA, sound, and has several USB ports and connects using a single USB cable.

The problem is sometimes after the CEO docks, the screen resolution sets itself way high so the screen is skewed across his 24: wide screen. Is there any way to lock the resolution to 1024 x 768?