On the off chance that this happens to anyone else, here's the solution, provided after multiple private messages with Dell tech support: Restart your machine and at the Dell logo, repeatedly tap the F2 logo to get in to BIOS.   Here look for POST Behaviour >> Fn Lock   Ensure this setting is enabled and Lock Mode Secondary is selected.  This worked! I am no longer tearing out my hair and swearing at my laptop.   
After a recent update of my two-year-old laptop, apparently, my home and end keys no longer work as normal. I can't hit "home" to get to the beginning of a line in Word or "control home" to get to the top of a document, an email or my inbox. The "end" button is even weirder - if I hit either "end" or "control end," I get the save menu in both Word and Outlook, but can't get to the end of a line or of the document or inbox. This is maddening after many years of using the home and end keys normally. To make things weirder, and harder to adjust to, these keys work as they always have on the external keybord I use when my laptop is in the docking station at my office. I have seen the guidance to use control-fn-home or control-fn-end to get to the top or bottom of a document or the inbox, and that works but is two more steps than I'd like to use. But I can't go to the start or end of a line that way.  Any advice on how to get my keys working as normal? I'm a lawyer with decent tech skills for standard uses but would need step-by-step guidance for any re-programming suggestions. Thanks, all.  
Home and end keys have stopped functioning