check your other quick buttons, like volume and capture. if you’ve lost them all it’s probably your graphics driver, delete it or roll it back, things should be better then.
Did you by any chance install the latest 14.0 graphics driver from Intel? If so, it disables the Magnify button feature. The only way to fix it is to roll back the driver or uninstall the driver and reinstall any pre-14.0 driver.