I too was surprised to see the Pause/Break missing.  Looks like Dell decided it is more important to have a cd eject button instead of the Pause/Break.  I am a programmer and need that key for debuggining purposes.  Fortunately, I was able to remap the F10 key to be Pause/Break.  There is a greak free keyboard remapping program called smartkey which can be downloaded from http://www.randyrants.com/2008/12/sharpkeys_30.html

Here is the registry setting for setting the F10 to act as the Pause/Break in Win XP. 

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Keyboard Layout]
"Scancode Map"=hex:00,00,00,00,00,00,00,00,02,00,00,00,46,e0,44,00,00,00,00,00