I have a T42 with resolution set to 1024 x 768 and a 19" Dell monitor with resolution 1280 x 1024. I have the laptop docked in a port rep and dual display setup between the laptop and the monitor with the monitor being the primary display. Not sure if resolution matters in this case but when ever I undock the laptop it inherits the monitors resolution so I have to drag the mouse down to get to the START menu. I was going to try to make the laptop my primary display just to see if that changed anything but I coulcn't switch it. It was greyed out.

Right click the desktop and select properties then settings. Under the box that shows the monitors as two rectangles, you will see a drop down window named Displays. Select the secondary monitor and look at the two check boxes under the selection, are both checked? If so uncheck the top box. Now select the one you want as the primary monitor and if its not already, check the top box (Use this device as primary monitor) click Apply then OK. Computers... designed to entertain,help with work but most of all to frustrate you!