No dell here but I do have this last XP machine.

by R. Proffitt Moderator - 3/13/13 4:43 PM

In Reply to: Fn key by pdh1945

Remember that each maker and even machine can change the method. Here's the screen I used.

http://i175.photobucket.com/albums/w146/rproffitt2000/changedisplay_zps07086d29.jpg

Your product manuals are at:
http://www.dell.com/support/Manuals/us/en/19/product/latitude-131l

The user manual does not appear to support changing of the primary display. But appears to note Fn+F8 and for more settings Dell's Quickset and not Windows Controls.
Bob