After I was told, after trying to find it for hours:
Some computers have a physical button to turn wifi on and off or keyboard button.
Some computers have a function button on the keyboard that turns that track pad on and off. There is also a setting in the Windows control panel that can enable or disable.
Common home network troubleshooting step. Unplug modem, router then wait. then plug in modem, then wait until lights are flashing, then plug in router.
If possible get the modem/router in one device. with many DSL providers you only need the one router can also have WIFi wireless network . check with your Internet Service Provider.
Full Screen mode:
To exit full screen mode it is now different with some programs. Sometimes it is ESC key or F10 or F11 and with Macintosh you may have to go to the top menu bar. To close a window in Windows use F4. To Quit a program in Macintosh use CMD Q
Sometimes restarting the computer can solve problems.