You probably can't turn off the WiFi with a Fn key, or adjust the volume either. I'll assume you have the L850D laptop and typed 'desktop' in error.
TOSHIBA SATELLITE L850D-138 asimpleman, Your specs are for a laptop, not a desktop. I've tried all methods on the Internet but none of them was successful. The FN and down-arrow or up-down keys don't working. I have a problem in my Windows 10 Home desktop.
